png-cmp: like cmp for PNGs

png-cmp is a program I built that checks if two PNGs are visually equivalent. It’s inspired by the cmp command. Here’s how you use it: png-cmp a.png b.png Like cmp, it silently exits if the images are identical, and gives an error if they’re different. Unlike cmp, it checks pixel data, not binary data. PNGs can look the same but be stored differently. For example, png-cmp ignores text metadata. I was recently doing an experiment where I wanted to check if two PNGs were visually identical, so I built a tool for it! Grab the source code here.