> I have a slightly OT question: is it reasonable that PNG versions of > an image may be bigger than their GIF equivalent and (less > sursprisingly) much bigger than their JPEG versions? I have not > tested this theory, but I have had this reported to me.
png is libz compression, so even at its best you can still have an image that compresses very badly. in fact i think i have an example, let me find it... here: http://pages.cpsc.ucalgary.ca/~mirtchov/screenshots/scr-porcini.png basically that image (an album cover i used as as a desktop background) even though small in acreage is large in size as a png (1.1 megs) at compression of 9 and there's nothing we can do about it. i don't care much about gif, but JPG achieves the small file size by being lossy. for a test open up a JPG image in gimp or whatever editor and save it again, but increase the level to 100% (instead of the usual 85 or 90): -rw-r--r-- 1 andrey andrey 1125261 Apr 27 00:28 IMG_3735-1.jpg -rw-r--r-- 1 andrey andrey 446941 Apr 26 17:18 IMG_3735.JPG (the images are otherwise unaltered)
