Below are three images of the Van Gogh
painting “Terrace of the Cafe at Night.” Their format and file sizes, from left to
right:
- JPEG progressive, with five bands;
21K. This is the smallest file, and therefore will of course have
the shortest download time. But JPEG has to be decompressed by the
browser, which offsets some of the saving from small file size.
- Interlaced GIF; 56K. Nearly three
times as large of course, but a low-resolution version begins to
show as the remaining lines are transmitted.
- Interlaced GIF, but using a palette
of only 32 colors: 26K. I can see a small quality difference between
the middle image, with its 256-color palette, and the 32-color
version.. But for most web purposes
I'd trade that subtle degradation for two-to-one reduction in file
size. But there is a limit: with a 16-color palette the quality is quite unacceptable.
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