The image is tiled on the background. Don't use a background that makes the text hard to read. Don't use large image files for the background. Tiled backgrounds should appear seamless See Page 3.16 for backgrounds. When a non-interlaced image is loaded, it loads in a similar manner, one line at a time from top to bottom.
Every nth line is retrieved, then another nth line is retrieved, etc. until fully loaded.
This makes the graphic appear blurry as it starts loading then get more and more clarity as more of the image loads. Transparent color With GIFs, you can specify a certain color to be transparent. When viewed on a web page, the background will show through the image. Animated GIFs Animated GIFs are a series of frames that are played sequentially. When played in rapid succession, the image is animated.