IMHO the right format for line drawings and such is either PNG or GIF, with the smallest being indexed PNG (GIF is 2nd smallest). JPG at 75% was about 4x bigger for my test case (screenshot of a PCB):
1145874 Dec 18 11:07 test.ppm the original, 24-bit uncompressed 20442 Dec 18 11:08 test.pngi indexed PNG 33623 Dec 18 11:08 test.gif indexed GIF 35326 Dec 18 11:08 test.png 24-bit PNG 115728 Dec 18 11:07 test.jpg 24-bit JPG And, of course, pretty much everything supports GIF.
