PNG Optimizer is a browser extension that helps 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 interface (top section) and then wait for a 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 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 the download location is the default location in your browser. Note 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 performances and results. 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 2: 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 out the bug report form on the add-on's homepage (https://mybrowseraddon.com/png-optimizer.html).