Size versus Quality I'm trying to figure out the relationship between the file size and the quality of digital images. To start, I've selected a JPEG image (a photo taken of an oil painting by a great artist...me!) The following series of images are all the same size, but I've progressively decreased the quality . IrfanView allows me to select options for saving JPEG or GIF images. The only option I changed for each of the following examples is that of quality, starting with 100% and decreasing to a minimum of 1% . Image #1: firefighter-400x312-100.jpg, 84 KB Image #2: firefighter-400x312-90.jpg, 28 KB Image #3: firefighter-400x312-80.jpg, 20 KB Image #4: firefighter-400x312-70.jpg, 16 KB Image #5: firefighter-400x312-60.jpg, 14 KB Image #6: firefighter-400x312-50.jpg, 12 KB Image #7: firefighter-400x312-40.jpg, 10 KB Image #8: firefighter-400x312-30.jpg, 9 KB Image #9: firefighter-400x312-20.jpg, 6 KB Image #10: firefighter-40