Optimizing Gif File Compression
Gif files use LZW file compression which is a "lossless"
compression. This means the image stays true when compressed. GIFs compress by
looking for repeating patterns of color along each horizontal line and compressing the
pixels. As the GIF scans across the image horizontally, wherever there are adjacent
pixels the same they are compressed together. Therefore the images that get compressed the
most contain the most repeating patterns along the horizontal.
| Lines running horizontally causes more
compact files. For example the full size version of this picture is 3209
bytes.
===> |
|
|
<=== The same full-sized
image rotated 90 degrees takes up 7994 bytes. The horizontal thumbnail version
above takes up 1498 bytes, while the vertical thumbnail takes 2249 bytes. |
|
