PNG Compressor
I have tried an excellent PNG file compressor online: TinyPNG. Usually this can compress a figure by about 60% without lossing visually detectable quality! This should always be used whenever possible.
Unlike JPEG, PNG doesn’t typically have a lossy compression scheme. What they can achieve is something I haven’t really found an alternative for.
I made a donation of $5 to them. Great work!
ffmpeg
has some built-in compressor when combining figures into movies, so it make less sense to compress each figure before passing them toffmpeg
.
This video explains many things about the differences between PNG and JPEG:
So basically, if you can count the number of colors in your image (e.g. most scientific plottings), use PNG. Even though PNG supports 24-bit colors, 8-bit (256 colors) is enough for most scientific images. This is the most important trick used in TinyPNG.