OptiPNG is an open-source PNG optimizer that recompresses image files to a smaller size in order to increase your overall website and page speed.
Many website managers and graphic designers compress their image files with online converters such as TinyPNG or compressJPG to make it faster and to save bandwith. Certainly, this is not always the most efficient method since you still need to reupload all compressed images to your CMS to re-implement them. If you have a lot of images on your website, this process can become very time consuming.