punypng is a free tool that dramatically reduces page load times by reducing the file size of an image without any loss of quality.
punypng uses several web optimization techniques to reduce the file sizes of your images. It first analyzes the content of your image and figures out the best image format to use.
Punypng will automatically convert your GIF into a PNG format and then further compress that. For JPEGs, sometimes it’s better to make it a PNG, and other times it’s better to keep it as JPEG and use JPEG translator to optimize it.
Based on typical images found on the web, punypng was benchmarked against other popular tools and libraries available. The results as follows.