GIF Animation on the WWW

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The photos below have very fine differences. Other images with different palettes will cause larger, more obvious variations. If I find better examples I will supply them. Note the small band of white at the base of the hill-near the center of the photo. It changes from a thin bright white band to a larger blurred-whitish band depending upon settings. The oranges and reds shift, and the dark areas caused by overhead clouds change from grays and green to blacks. Fifteen-bit Quantize produces the image closest to the original. Different images may require different settings.

USE A LOCAL PALETTE
This increases the files size by as much as 779 bytes. A new palette of colors is generated for this image only. The only problem I see is some 256-color displays may not handle too many palette swaps very well. You may see what appears to be a colorful negative images, or flashes on screen.
USE A LOCAL GREY PALETTE
This inserts a palette that is composed of 256 levels of gray. Color #0 is black, color #1 is white, and #2 through #255 range from near-black to almost white. You can use this to convert a color image to grayscale. Though, because of sorted palettes this method of conversion will often leave the image very dark.
REMAP IMAGE TO THE GLOBAL PALETTE
Similar to DITHER below. GIFCon simply replaces colors absent in the global palette with one that is closest to it. REMAP is not a good option for photographic images.
DITHER IMAGE TO THE GLOBAL PALETTE
This means that GIFCon will repaint your image to make up for colors that are not in the global palette. This may include using a dot of red and a dot of orange next to eachother to get that odd brownish-orange color you used. This is known as dithering. This is best for photo-like images. Some detail may be lost.
USE AS THE GLOBAL PALETTE
You only get this option once. One image can have its palette copied into the global palette. Once done, you canít choose another. For this reason I suggest picking your global palette first, rather than do it as an afterthought.
USE AS IS (MAY CAUSE COLOR SHIFTS)
This option causes a GPF in GIFCon when I go to save. Be very cautious if attempting to use it. What this means is: whatever color #0 is, use that color for #0. Whatever color #253 is, use that color for #253. You see GIFs work like a color by number set. If a particular pixel is color #197, the decoder goes to the color palette, finds #197 and paints the pixel that color. USE AS IS will simply use the GLOBAL palette, whether it has any relationship to the image or not. This option usually does not work. The posterized result here is a common result.
FIFTEEN BIT QUANTIZE
This option will produce more attractive images if your palette requires color matching and remapping. However itís also pretty slow, especially on older machines. It does, however produce smoother gradients, and more excat representations of higher color images.

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Any ideas, suggestions,utilities, or examples, please mail them over for inclusion in this page.

Royal Frazier