Crunch – lossy PNG image file optimization
Lossy compression is a data encoding method which reduces a file by discarding certain information. When the file is uncompressed, not all of the original information will be recovered. Lossy compression is typically used to compress video, audio and images, as well as internet telephony. The fact that information is lost during compression will often be unnoticeable to most users. Lossy compression techniques are used in all DVDs, Blu-ray discs, and most multimedia available on the internet.
Images take up massive amounts of internet bandwidth because they often have large file sizes. They are the most popular resource type on the web. According to the HTTP Archive, the majority of the data transferred to fetch a web page are images composed of JPEGs, PNGs and GIFs.
Crunch is a command line program that performs lossy optimization of one or more PNG image files with pngquant and zopflipng. It’s free and open source software.