Every time the topic of lossy-versus-nonlossy compression comes up on some web-mail list, it usually devolves into a pretty heated argument between several viewpoints:
In fact, the only viewpoint that doesn't seem to have any adherents left anymore are the folks who are content with ASCII art or GIFs. What's most amazing, to me, is that very few people actually do their own tests to perceptively evaluate images.
What are we measuring here? It depends. We may be measuring how good your eyes are. We may be measuring how good your screen/display is. We may be measuring how good your graphics adapter is. We may be measuring whether or not you can tell a 90% JPEG from a 100% JPEG. In the end, my objective is simple: I just want to get you to think a little bit about image quality and perception, so that next time the lossy-versus-nonlossy compression debate comes around, you'll be armed with some opinions based on personal experience.
You will be presented with a sequence of pairs of images. One of the two images will be a lossless PNG written by photoshop, and the other will be a JPEG (quality between 7 and 12) also written by photoshop. The program will not tell you which image is which; simply click on the one that looks better to you. You will be presented with feedback as to how you perform. Clicking "Back" on your browser will not allow you to re-assess a given image, you must run the test to completion or quit out.
Click Here to Begin The Test
(It'll take a while to load since it preloads all the images, about 3MB in all. Be patient!)
Morrisdale, PA Jul 9, 2005