PNG Optimizer is a browser add-on that help you optimize PNG images. It also reduces the file size depending on the optimization level. Simply drag & drop PNG file(s) to a designated area in the app UI and then wait for few seconds for the optimization process to finish up. You can choose your desired optimization engine from the drop-down list as well. The first and last engines can optimize both PNG and JPEG files, but other engines are designed for PNG files only. All the info about the optimization process is being displayed in the console area within the app UI. Once the optimization process is done, please click on the download button to download the optimized image. Please note that download location is the default location in your browser. Note (v0.1.1+): PNG Optimizer add-on uses 5 different open-source optimization engines: optipng.js, pngcrush.js, pngquant.js, compressor.js and browser-image-compression.js. Optimizer engines have different performance and result. Please use the one that best matches your need. 1) optipng.js: https://github.com/LI-NA/optipng.js/blob/master/demo/js/optipng.js 2) pngcrush.js: https://github.com/richardassar/pngcrush.js/blob/master/pngcrush.js 3) pngquant.js: https://github.com/psych0der/pngquantjs/blob/master/demo/js/pngquant.js 4) compressor.js: https://github.com/fengyuanchen/compressorjs/blob/master/dist/compressor.js 5) browser-image-compression.js: https://github.com/Donaldcwl/browser-image-compression/blob/master/dist/browser-image-compression.js Note: because this is an ongoing project, you might see some bugs in optimizing image files. If you found a bug to report, or have a feature request, please fill the bug report form in the add-on's homepage.