One JPEG format has a JPEG header that is shared between multiple JPEG images in a single Macromedia Flash (SWF) file to minimize file size. Another JPEG format lets each image have it's own header, allowing each image its own compression settings. The zlib format is similar to an embedded PNG file and is used when you need lossless image compression. This is best for images that would compress well as a GIF file like screen shots or diagrams, while JPEG is best for photographs.
发表于 2012-5-11 13:34:00
