# Imagesharp.Tests.Images External image repository to support ImageSharp testing. It's main purpose is to hold reference images for regression tests. ### ReferenceOutput Contains images to validate against in ImageSharp tests. In most cases the file hierarchy follows the hierarchy of `ActualOutput` ### tools Various utilities to help dealing with images. - `optipng.exe`: [lossless PNG compressor](http://optipng.sourceforge.net/), to keep the `ReferenceImages` repository as small as possible - `optimize-all.cmd`: Runs lossless optimizer for reference PNG-s. Currently it has to be manually edited to add new test class directories. - [`dump-jpeg-coeffs.exe`](https://github.com/SixLabors/Imagesharp.Tests.Images/blob/master/tools/jpeg/README.md)