Whether you're designing a website, writing a blog post, or organizing your photos, sometimes you'll find yourself with a handful of pictures that need to be processed en masse—and doing them one by one can end up being a huge waste of time.

There are plenty of batch resizing tools out there, but many of them require installation—and most are limited to one particular operating system. In a lot of cases, it's faster and more convenient to use free online tools instead.

We've compiled a list of the best online tools for batch image processing and categorized them in three ways: resizing, optimizing, and converting. Bookmark the ones you find useful and start using them now!

Image Resizer Tools

Image Resizer website

Image resizers can be tricky, not only because of file size considerations but also because resizing can affect the quality and clarity of images or videos. Some resizers are better than others, and you'll find some of the best tools below.

1. Bulk Resize Photos

Bulk Resize Photo website

Bulk Resize Photos has one of the easiest interfaces. Just drag your images onto the site—as many as you want—and you can scale in six ways: percentage, file size, longest side, dimensions, width, height, or longest side.

Everything is client-side, so it's really fast and no uploading is necessary. You can also use the advanced settings to convert images to JPG, PNG, or WEBP, along with adjusting image quality, setting the background color, and even adding padding to prevent stretching.

2. BIRME

BRIME website

BIRME, which stands for Batch Image Resizing Made Easy, is another robust image resizing tool. It is simple but flexible. Simply drag your images onto the page and set the new width and height. Depending on which resize option you select, it will scale or crop to fit your dimensions.

It can also add some border padding and alter quality settings (for JPEGs). Resized images are downloaded as single files or as a ZIP file.

3. Online Image Resize

Online Image Resize website

This is another easy-to-use online image resizer that allows you to resize your BMP, GIF, JPG/JPEG, or PNG files. However, you can only use it to resize an image's width.

It allows you to upload files that are up to 20MB in size. Online Image Resize is completely free to use, and any image that you upload will be deleted from its servers after 30 minutes.

4. RedKetchup

RedKetchup website

RedKetchup is a simple but powerful online image editor that also allows you to quickly and easily resize your photos. It also allows you to compress and convert multiple photos at once, among many other functions.

Using its Configure Batch settings, you can resize by percentage, exact dimensions, file size, width, height, and longest side. You can also add a background, sample, and filter, as well as sharpen and add color depth to your photos.

5. PicResize

PicResize website

PicResize allows you to batch resize up to 100 images at once. You can also use it to convert, crop, rotate, or compress images. It is a batch resizing tool that is still useful and also gets the job done.

You can use it alone or in combination with other picture resize tools covered here. If you switch to the non-batch version of PicResize, you can also crop and add special effects to your images.

Image Optimizer Tools

Image optimizers have one primary focus: to reduce the file size of an image as much as possible while impacting the quality of that image as little as possible—all without resizing or cropping the image.

6. TinyPNG

TinyPNG Website

TinyPNG is arguably one of the best image optimization tools on the web. Despite the name, it can compress WEBP, PNGs, and JPGs. There's absolutely nothing you have to do other than upload the images (which uses a lovely drag-and-drop interface).

Once uploaded, TinyPNG automatically compresses using a lossy method that maintains the perfect balance between quality and file size reduction. Files can be downloaded individually, as a single ZIP file, or moved to your Dropbox account.

7. Optimizilla

Optimizilla website

Optimizilla is very similar to TinyPNG in that you just drag and drop GIFs, PNGs, and JPGs, and it does most of the work for you. However, with this, you can control the final quality of the images (between 1% and 100%) on a per-image basis.

The downside is that you can only process 20 images at a time. Files can be downloaded individually or as a single ZIP file.

8. Kraken.io

Kraken website

Kraken is another drag-and-drop tool that's a bit more restrictive than the above tools but has one big advantage: you can choose whether to compress using a lossy or lossless method. You can download the resulting images individually or as a single ZIP file.

The restrictions: Up to 1 MB per image and a total of 50 MB per month. You can get a premium subscription to increase the file size limit to 32 MB, the monthly upload limit to gigabytes, and unlock extra features like resizing and Dropbox synchronization.

Image Converter Tools

Different image formats have different pros and cons—check out our comparison of JPG, PNG, and GIF—and often, it makes more sense to prioritize one format over others. These tools come in handy when you want to switch a lot of images to a particular format.

9. Raw.Pics.io

Raw.Pics website

Raw.Pics.io isn't just a handy tool, but it's beautifully designed too. It makes you want to use it, and that's rare among online tools (which tend to be hastily thrown together).

As a photography-centric tool, Raw.Pics.io mainly supports RAW source files in the following formats: DNG, CR2, NEF, ARW, ORF, PEF, RAF, PDF, or JPG. Images can be exported as JPG, PNG, or WEBP. Only JPG source images can be resized.

10. CloudConvert

CloudConvert website

CloudConvert is an incredible tool for any kind of file conversion. You can upload images from your cloud account (either Dropbox, Google Drive, OneDrive, or Box), your computer, or via URL. It also supports a dozen image inputs and output formats.

For free, you get 25 conversion minutes per day. You also get five concurrent conversions, 1 GB max file size, and bumped down to low priority if there are lots of others using CloudConvert at the same time. For more freedom, you can upgrade to a premium subscription starting at $8 per month.

Easily Bulk Resize, Optimize and Convert Your Photos

There are several other online image editors that you can use to bulk resize, optimize, and convert your photos apart from the ones covered above. While choosing, confirm that your photos are uploaded client-side.

In the rare event that your photos are uploaded to a centralized server, confirm that they will be deleted after a few minutes. Some of such sites actually allow you to delete your uploaded files yourself at any time.

Note that if you're using one of these tools as a photographer, and you have aspirations to be professional or semi-professional, we recommend learning to use something like Photoshop or Lightroom instead.