Mac

How to Resize Images on Mac Using Photos or Preview

Sandy Writtenhouse Updated 13-02-2020

If you want to resize images on your Mac, you don’t need an expensive app to do it. Fortunately, macOS provides you with a few built-in tools that you can use to resize your images easily.

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Here’s how to resize an image on Mac quickly using Preview, Photos, ColorSync Utility, and even the Mail app.

For Most Tasks: Resize Using Preview

Preview is a robust app that you can use for all sorts of tasks like viewing images, reading documents, and even signing PDFs. One of its most useful features is the ability to resize images, which is a task that Preview makes simple.

Preview does not require you to import an image into a library first, and it lets you unlock the aspect ratio so you can stretch or squish the image if you want to. For that reason, Preview is the best choice when it comes to quick resizing jobs for images other than those in your Photos library.

To resize an image with Preview:

  1. Double-click on your image to open it with Preview, if it’s your default image viewer. You can also select multiple images in Finder, right-click, and choose Open With > Preview.
  2. Click Tools > Adjust Size from the menu bar.
  3. Use the Fit into box to specify a preset value or input your own width and height into the boxes provided.
  4. Select the dropdown box to choose from pixels, percent, inches, or another unit.
  5. Optionally, you can check the box for Scale proportionally to retain the aspect ratio.
  6. Hit OK when you finish.

preview resize image

You can then save your resized image using File > Save or Save As (by holding the Option key). Alternatively, you can click File > Export to specify a file format and image quality. Check out our tutorial for additional image edits you can make using Preview How to Edit Photos on Mac Using the Preview App Your Mac's Preview app can do a lot more than just display images. Here's how to edits photos on Mac using Preview. Read More .

Resize Images Using Photos

Apple replaced iPhoto with the new Photos app in 2015. Nowadays, most people are more familiar with the Photos app than its predecessor. As it turns out, you can use Photos for more than looking at your images. It lets you edit RAW photos, import your own custom filters, and even create slideshows.

You’ll need to import an image into your library before you can edit it in Photos. Images you add from your iPhone, digital camera, or SD card should already be in your library. If you have images from the web or other sources, you can drag them onto the Photos window or click File > Import from the menu bar.

From there, here’s how to resize an image in Photos:

  1. Open Photos and select your image(s).
  2. Click File > Export 1 Photo (or however many you are resizing).
  3. Under Size you can choose the Full Size, Large, Medium or Small presets. Custom allows you to set your own size (in pixels).
  4. Choose Custom to specify a maximum Width or Height, or choose Dimension to limit both width and height to the number you provide.
  5. Optionally, you can choose the file type, compression quality, whether to omit embedded location information, and pick a color profile if you like.
  6. Click Export and choose where you want to save the image.

photos resize Mac

Note: You also have the option to Export Unmodified Original, which is what you should choose if you’re printing your images or plan on working with them in an external photo editor The 8 Best Free and Paid Image Editors for Mac Here are the best free and paid Mac image editors, whether you're a professional professional or amateur shutterbug. Read More like Photoshop or Pixelmator.

Resize Images Using ColorSync Utility

ColorSync Utility is one of those default Mac apps The Best Default Mac Apps That You Shouldn't Need to Replace Here are some of the best default, pre-installed, native Mac apps worth using. Don't ditch them before you try them! Read More you might not even know exists. Its purpose is to help you finely control color profiles on your system. But you can also use this hidden gem to resize images in a hurry.

One point to note about using ColorSync Utility to resize an image: images resized in this way must maintain their aspect ratio. To get started:

  1. Select the image in Finder, right-click, and choose Open With > ColorSync Utility.
  2. At the top of the window, click the Adjust Image Size button.
  3. Choose scale, width, or height in the Resize dropdown and enter the value in the To box.
  4. You can optionally adjust the Quality and Set DPI settings.
  5. Click Apply.

ColorSync Utility Resize Image Mac

You can then click File from the menu bar and pick Save, Save As, or Export to save the resized image.

Resize Images Using Mail

If you want to resize an image on your Mac simply to attach it to an email, you can actually resize that image in the Mail app itself:

  1. Open the Mail app to the email you’re composing.
  2. Attach the image by dragging it into the body of the email or by clicking the Attach button in the toolbar to locate and insert the image.
  3. With the image still selected in your email, click the Image Size dropdown box and select a different size. You can pick from Small, Medium, Large, or of course, the actual size.
  4. Finish composing your email and send when you’re ready.

Mail App Resize Image Mac

While you can’t resize an image in Mail to a specific size, if you only want to resize it so that it’s smaller for the email message, then this is convenient.

For Legacy OS X Users: Resize Images Using iPhoto

If you’re using an older Mac that isn’t compatible with the latest version of macOS, it’s possible that you still have iPhoto. So for you legacy Mac users, here’s how to resize your images with iPhoto.

In order to resize an image with iPhoto, that image must be in your iPhoto library. If you use iPhoto to import your images from an iPhone or digital camera, then this is already done. If you’re grabbing an image from the web, the best way to import it is by dragging the image into an iPhoto window.

Once you have the image in your library, you can export and resize it as you see fit. iPhoto will maintain the image aspect ratio, so you can’t stretch the image unnaturally. Resize by following these steps:

  1. Open iPhoto and select your image(s).
  2. Click File > Export.
  3. Under Size you can choose Full Size, Large, Medium or Small presets. Custom allows you to set your own size (in pixels).
  4. Choose Custom to specify a maximum Width or Height, or choose Dimension to limit both width and height to the number you provide.
  5. Hit Export and choose a location to save the image.

iphoto resize

You can also choose the file type, compression quality, whether or not to strip location information, and set a prefix filename. The latter is handy for exporting a series of images that follow a naming convention.

Resize an Image With Little Effort on Mac

Any of these built-in apps gets the job done when you want to resize an image on Mac. For example, you might use Preview most of the time, but take advantage of the Mail image resizing feature here and there. Whichever way you decide to go, you have options to make the process convenient.

Meanwhile, if you’re interested in resizing a batch of images on your Mac How to Batch Convert and Resize Images on Your Mac Don't waste time converting and resizing images separately! Here's how to quickly batch convert and resize images on your Mac. Read More , we have a tutorial for that too!

Explore more about: Batch Image Editing, Image Editing Tips, Image Editor, iPhoto, Photography, Preview App.

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  1. Andrew
    June 20, 2018 at 2:06 pm

    What I'd really like to know is how to have iPhoto NOT resize my images! They are the full 12 Megapixel size in iPhoto but whenever I copy the photos from iPhotos to a folder in Finder, or copy to an email, they reduce in size! It is so damn irritating that I can't simply send the original file.

  2. Ra Ra
    November 25, 2017 at 5:53 pm

    This article was so helpful. I was tearing my hair out trying to figure out how to resize my image. Thank you for writing such clear, informative instructions for non techies like myself!

  3. reybo
    April 24, 2017 at 4:08 pm

    NONE of the options below are in Photos v1.5 for El Capitan. The Export allows no change of the image in Photos.

    [No Size function there] Under Size you can choose Full Size, Large, Medium or Small presets, and Custom allows you to set your own size (in pixels).
    Choose Custom to specify a maximum Width or Height, or choose Dimension to limit both width and height to the number you provide.

    • Tim Brookes
      May 5, 2017 at 4:32 am

      Photos is currently on version 2.0, and the above tutorial works perfectly (I just double checked it).

      I suggest you update your Mac or try again?

  4. Gregory252
    November 12, 2015 at 1:23 pm

    That is why I always prefer to do the things with a Photoshop instead of any other program. All other softwares are not good as Photoshop and for me personally it is the most simple solution. Image Size menu have everything for perfect resizing photos so who is beginner maybe can check this tutorial : http://pc-problem-solutions.blogspot.rs/2015/11/how-to-resize-photo-in-photoshop-cs3.html . Do not complicate your life with useless things like photo resizing...

  5. bunny
    June 5, 2011 at 7:06 pm

    Actually, even though resizing appears to be simple two-click process in Preview, images continue to PRINT out in the full/original size rather than at the "resize" selected. Does anybody have a solution for that.

  6. Egqegwe
    May 15, 2011 at 1:18 am

    It should be as simple as File-->Resize then it takes you to a dialog that says "Height __ PX" and "Width __ PX"

    • Egqegwe
      May 15, 2011 at 1:25 am

      Even easier, you can use Preview instead of iPhoto, then go to Tools-->Adjust Size. iPhoto is junk

  7. Bakari
    March 29, 2011 at 2:40 pm

    OttifantSir, I’m not a Mac fanboy trying to defend Apple’s products. There are many times I get just a frustrated as you about why certain features or processes are missing in Apple software, or any software for that matter. As for resizing photos in iPhoto, I’m personally don’t see it as difficult as you describe. I read your comment two times, and maybe I’m missing the point and the specific problem. I apologize for not seeing that.
    Why do you find selecting a photo and clicking File>Export, and choosing a resize option as such a huge problem? Could suggest a better way that it could be done? This is a real question, not a defense of Apple. IPhoto is not Photoshop, but on this particular case, I’m sorry but I’m just not seeing your point. Finally, please don’t take my response as one of arguing with you. I’m just trying to get clarity about your concerns.

  8. OttifantSir
    March 23, 2011 at 8:44 pm

    No resize tool available for Apple's iPhoto? And it costs money? This really shows that Macheads are just a bunch of cult-mmbers under The Church of Jobs.

    And they will now come and defend their precious program, saying it can resize, and how could I not have read the article, just the headline. I DID read the article. There's two ways this article describes as ways of paying (if you didn't spend some extra money already when you bought your Mac) to resize your pictures: Email them, or export them. Preferrably to a different format it seems.

    But I am not interested in the POSSIBILITY of resizing pictures with iPhoto. Every Apple-fanboy and -girl out there says Mac is SOOOOO easy to use. "You just sit down, and presto!, two minutes later you're surfing the Web with the same ease as someone who's spent days, or even weeks, configuring their Windows-PC. And don't start me on that geek-only OS Linux. Who the h*** wants to mess around with settings on their computer?" I am interested in the USERFRIENDLINESS of iPhoto. And this article shows me iPhoto ISN'T userfriendly. I can't tell how many times I've met limitations on image size online. If I had had a Mac, I wouldn't have been able to post those pictures.

    Macheads again: "But you can just email them to yourself or export them!" Yes, and after a while I might have found out that. But I also have more than 20 years experience with computers, and I know that if you're looking for a tool, it's not always obvious, and the menus aren't there ONLY for the professionals. But, take my family: Mom needed practically a two-day course in using Picasa. My sister doesn't even know how to install/uninstall a program without a 7-page booklet from me with pictures. My father doesn't care about computers, except for being pro-Windows. My brother can't be bothered to learn anything besides setting up Call of Duty and play that. Somehow, they all take pictures and load them onto their PC. Sometimes they upload them, and sometimes they need to resize them.

    I know what the reactions would be to iPhoto. Mom: Can you help me resize my pictures? Why do you do that? Why isn't there a button or choice to resize? (Two days later, on the phone) How did I resize my pictures again? You got to come over and help me. Now. Sis: I tried using it, but I wanted to resize some photos, and couldn't, so I gave it up. D***! POS program can't even do that! It was so easy in Windows (Paint.net, Picasa, Gimp, built-in, etc), why is it so hard on a Mac? I'll never again use ANYTHING from Apple. Dad: What does it do? Show pictures? Can it do more? Email pictures, huh? That's a nice touch. (Three weeks later, on the phone) My buddy can't see the pictures, they're too small. I tried using the other choices, but then he can't receive my e-mail, it's too big. Can you help me? Brother: (Six months later) I just tried importing my pictures to iPhoto a few months ago, but something went wrong. I don't know what, and I haven't tried anymore since, so I don't know if it's fixed or not. (I sit down, he tells me what he did, no problem importing) Huh, guess it's fixed then. (Three months later) The day after you helped me with iPhoto, I tried importing some other pictures, and the fault came up again. Can you come over some day and fix it again? (I know, importing and resizing are two different things, and importing pictures is available and easy in practically all image editors. But, that's my brother's view)

    As you can see, there's a point to this story: I am the geek, and I am expected to know the solution to all their computer problems, even if I, as in the case of Apple-products, have never owned or used any of them. And also, if Macs are supposed to be so userfriendly, then why hide one of the most important and easily implemented features under the un-intuitive heading of Export in a menu. Why not right-click? Oh, that's right. Macs don't have two buttons on their mouse. If you want a right-click menu, you have to CMD-Click. (I wonder if that's the reason why, after 20 years of Windows and Linux experience, when I try a Mac at a computer store, it's impossible to do anything but look at the background and the dock. I know they're locked down to some degree, but I should be able to open the programs to see the interface, right?)

    (Climbing off my soap box....)

    In short: Thanks for showing the world how idiotic Apple is in their GUI-decisions.

  9. Christian Hagen
    March 23, 2011 at 7:44 pm

    No resize tool available for Apple's iPhoto? And it costs money? This really shows that Macheads are just a bunch of cult-mmbers under The Church of Jobs.

    And they will now come and defend their precious program, saying it can resize, and how could I not have read the article, just the headline. I DID read the article. There's two ways this article describes as ways of paying (if you didn't spend some extra money already when you bought your Mac) to resize your pictures: Email them, or export them. Preferrably to a different format it seems.

    But I am not interested in the POSSIBILITY of resizing pictures with iPhoto. Every Apple-fanboy and -girl out there says Mac is SOOOOO easy to use. "You just sit down, and presto!, two minutes later you're surfing the Web with the same ease as someone who's spent days, or even weeks, configuring their Windows-PC. And don't start me on that geek-only OS Linux. Who the h*** wants to mess around with settings on their computer?" I am interested in the USERFRIENDLINESS of iPhoto. And this article shows me iPhoto ISN'T userfriendly. I can't tell how many times I've met limitations on image size online. If I had had a Mac, I wouldn't have been able to post those pictures.

    Macheads again: "But you can just email them to yourself or export them!" Yes, and after a while I might have found out that. But I also have more than 20 years experience with computers, and I know that if you're looking for a tool, it's not always obvious, and the menus aren't there ONLY for the professionals. But, take my family: Mom needed practically a two-day course in using Picasa. My sister doesn't even know how to install/uninstall a program without a 7-page booklet from me with pictures. My father doesn't care about computers, except for being pro-Windows. My brother can't be bothered to learn anything besides setting up Call of Duty and play that. Somehow, they all take pictures and load them onto their PC. Sometimes they upload them, and sometimes they need to resize them.

    I know what the reactions would be to iPhoto. Mom: Can you help me resize my pictures? Why do you do that? Why isn't there a button or choice to resize? (Two days later, on the phone) How did I resize my pictures again? You got to come over and help me. Now. Sis: I tried using it, but I wanted to resize some photos, and couldn't, so I gave it up. D***! POS program can't even do that! It was so easy in Windows (Paint.net, Picasa, Gimp, built-in, etc), why is it so hard on a Mac? I'll never again use ANYTHING from Apple. Dad: What does it do? Show pictures? Can it do more? Email pictures, huh? That's a nice touch. (Three weeks later, on the phone) My buddy can't see the pictures, they're too small. I tried using the other choices, but then he can't receive my e-mail, it's too big. Can you help me? Brother: (Six months later) I just tried importing my pictures to iPhoto a few months ago, but something went wrong. I don't know what, and I haven't tried anymore since, so I don't know if it's fixed or not. (I sit down, he tells me what he did, no problem importing) Huh, guess it's fixed then. (Three months later) The day after you helped me with iPhoto, I tried importing some other pictures, and the fault came up again. Can you come over some day and fix it again? (I know, importing and resizing are two different things, and importing pictures is available and easy in practically all image editors. But, that's my brother's view)

    As you can see, there's a point to this story: I am the geek, and I am expected to know the solution to all their computer problems, even if I, as in the case of Apple-products, have never owned or used any of them. And also, if Macs are supposed to be so userfriendly, then why hide one of the most important and easily implemented features under the un-intuitive heading of Export in a menu. Why not right-click? Oh, that's right. Macs don't have two buttons on their mouse. If you want a right-click menu, you have to CMD-Click. (I wonder if that's the reason why, after 20 years of Windows and Linux experience, when I try a Mac at a computer store, it's impossible to do anything but look at the background and the dock. I know they're locked down to some degree, but I should be able to open the programs to see the interface, right?)

    (Climbing off my soap box....)

    In short: Thanks for showing the world how idiotic Apple is in their GUI-decisions.

    • Boggle-trotsky (I'm too cowardly to use my real name because the comment is negative)
      September 20, 2018 at 8:36 am

      Nobody will ever read that screed.