So, which to use? Obviously every image varies but for a quick example, the image iTunes created in Photoshop incorporates a wide vaiety of textures - flat color, gradients, images etc. Here's what we found:
Original PSD document: Finished size 3.44 Mb.
Saved as JPG: Poor quality on the "sharp" areas and text. File size became 330.7Kb. An estimated download time of Broadband 1.0 Mb/sec (as were the remainder of the formats) was 4 seconds
Saved as GIF: Much better quality than before, however there was some dithering in gradient areas, which all but disappeared when the Colors were increased to 256. File size 125.9Kb, download time 2 seconds.
Saved as PNG-8: Slight dither in gradient areas otherwise excellent quality. File size 79.85Kb, download time 2 seconds.
Saved as PNG-24: No dither, excellent quality. File size 263.8Kb, download time 4 seconds.
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