If you are a quick fingered photo-snapper or a wallpaper junkie then the thousand of images on your hard drive could be a treasure hoard. But scattered among them could also be a few hundred duplicate images eating up space on your hard drive. Even worse, un-optimized raw images could be eating up chunks of bytes and can be officially called junk.

So, how do we go about covering up our laziness and cleaning up our image folders?

With some free software of course! Here's a list of 5 software apps (in no relative order of merit) that can find duplicate image files.

Dup Detector

Dup Detector requires that all images be in one folder. After that it starts with its job by comparing pixel data for each image. It records it all in a data file and finds duplicate images by comparing the closeness of the pixel data. The software starts off by displaying a four tabbed interface - Method, Get Data, Find Dups and View Dups.

The 'Method' tab gives you the option to find duplicates in a single photo collection, between two collections or just compare a single image to all images in a collection. 'Get Data' enables you to open an existing data file (i.e. a list of images) or build a new data file. The 'Find Dups' tab is where you can play around with the matching criteria like percentage match, colour and luminance. The 'View Dups' is the results tab displaying the matched images. You can setup the software to do a manual delete, a semi-automatic delete or an automatic delete.

Dup Detector supports the following image file formats - jpg, bmp, png, tif, pcx, tga, wmf, emf, psp.

The installed application has a small footprint of 1.94 MB and can also be downloaded from this alternate site.

Supported OS: Windows XP and 2000 (Not tried on Vista)

DupliFinder

DupliFinder scans and checks image similarities by analyzing the MD5 sum (i.e. the digital fingerprint) of each file. The interface is stark and it lets you browse to your image folder or drag and drop it directly into the program. It lets you check folders or sub-folders for images which are identical and also for photos which are similar. Thus, you might get find related as well as duplicate photos in the results window. The preview helps you to choose which ones to delete. The scan speed is a bit sluggish especially for large image folders but the comparison results are close to the mark.

The 407 KB software runs as a standalone executable and requires Java 1.5.

Supported OS: Windows, Linux

DoubleKiller

As its name suggests, it searches for "˜double' copies of all types of files employing any combination of name, size, modification date, or content. You can also employ wildcard searches and filter results using masks or attributes like file size range or files with certain properties like "˜read only', "˜hidden' etc.

The results are displayed at the end of the scan and here you can manually or automatically select the files to be deleted. The results can also be exported as a tab-delimited text file which can be imported into a spreadsheet application.

The 793 KB standalone program comes as a free version and also as a paid version with more sophisticated features.

Supported OS: Windows

SimilarImages

SimilarImages finds duplicate images on the hard drive using a "˜graphics library' which checks the images for compositional similarities. The results depend on a configurable similarity threshold value which can be set by the user or left at the default mark. The program can handle a wide variety of image formats and searches for similarities using the Normal, Inclusive (only within the same source-directory), or Exclusive (Only outside the same source-directory) search modes. The program also has a feature to process only new files by a certain date.

The results window comes with two image panels and includes several actions like deleting one or both files and swapping files (replace one with the other). Using the "˜Semi-automated Deletion' function one can also pre-select one file from the duplicates counting on the user-configurable rules.

Supported OS: Windows

VisiPics

I usually like to save the best for last and in my humble opinion it is this 1.9 MB software amongst the free bunch. VisiPics employs five image comparison filters to see how similar pairs of images on the hard drive are.

For instance, the software can mark out two identical image files but with different resolutions as duplicates, or the same picture but in different formats and even duplicates where only subtle compositional changes have taken place. Similarity checks can be set using a slider.

Detected duplicates are shown side by side as thumbnails and also in a larger preview window. The images can be flagged for deletion, they can be renamed and can also be moved to another location. The auto-select mode let you choose if you want to keep the higher resolution picture, uncompressed file types, smaller files or all of the above. The single window interface is easy on the eyes and the brain. It is also fast and as the software wiki says about the software - tested on 100.000 pictures, 15 GB archive, full results in 3 hours only.

Supported image formats include JPEG, GIF, PNG, BMP, PCX, TIFF, TGA and RAW

Supported OS: Windows

So if you are a photo buff, which software would be a must-install for you? Do you know of any other free tool which makes hunting down duplicate files free and easy? Let us know...