• HOW



  • HOW TO



Duplicate Photo Finder Explained

How duplicate photo finders work?

Duplicate Photo Finders are dedicated tools for finding duplicate images. In order to understand how a Duplicate Photo Finder works one should know how a digital photo is stored.

A digital photo is represented by dots with different colors named pixels. The count of the horizontal and vertical pixels determines the resolution of the picture. As the quantity of those pixels is large they are usually compressed when stored in a file and decompressed when they have to be displayed.

The different file formats have different way of compression and different way of storing those pixels. That is why the same image stored in different file formats has totally different data representation on the storage.

This is the reason why a standard duplicate file finder can not identify duplicate images even if they are absolutely identical and stored in different file formats - because they compare the file data instead of decoding that data and comparing the actual photo that it represents.

Why a duplicate photo finder is better than a standard duplicate file finder:

  • Identify duplicate images regardless of the image format.
  • Search for similar images based on a sample or multiple sample photos.
  • Compare and synchronize photo folders or libraries.
  • Delete duplicate photos to save valuable disk space

What are the most important features of a Duplicate Image Finder tool?

List of the most important options that a duplicate photo finder should implement in order to be able to handle most of the tasks.

Precise Detection

A good image analysis algorithm is the most important part of a good duplicate photo finder tool. It should be able to find similar images too.

Multiple Image Formats

As finding similar and duplicate photos requires image decoding, the more image formats a tool supports the more duplicate photos it can find.

Flexible Options

Options for filtering files, settings "source" folders, excluding files or folders, makes it easier to complete more complex tasks.

Move, Delete, Copy

Multiple actions for the listed duplicate photos should be supported in order to remove or backup the duplicates.

Compare & Search

Features to compare two or more folders or search for similar photos by sample images. Options to synchronize photo folders or merge new images to existing photo library.


High performance is extremely important in image analysis as the amounts of data are huge. A slow tool may need days to compare even several thousand images.