Letters From Somnolescent

I’ve become mildly obsessed with how compression algorithms of various stripes work over the past year. They really do make every bit of our modern computing existence work so smoothly, from gzipping packet data to speed up slow connections to storing vast archives of high quality music on flash drives the size of a ChapStick. Some simply rearrange the data in clever ways, and others take advantage of our weak eyes and ears to throw out 90% of what was once there–and we hardly notice.

Of the lot, the humble PNG is so ubiquitous, it might not even warrant mentioning. Every format has some magic up its sleeve, however, and in the case of PNG, the way they’re encoded usually makes it possible to shrink them after the fact to the tune of up to a few megabytes with no loss in quality. If you make sites, you might wanna take notes.

I recently decided to run a battery of tests to determine just how well PNG works, on what, and what optimizes the best. I’ll give you the rundown on how it works (in-depth but no math, no worries), and then I’ll give you some hard data and lovely charts to peek at, and finally, show you how to get smaller, lighter PNGs at home, no tricks, no catches. Continue reading →