Using the correct Image Format

From digg a great article on picking the correct image format. The article summary captures it all,

• JPEG:
  • Good:
    • Photographs
    • Game screenshots
    • Movie stills
    • Desktop backgrounds
  • Bad:
    • Windows application screenshots
    • Line art and text
    • Anywhere where fine lines or sharp color contrast is needed
• PNG:
  • Good:
    • Text, line art, comic-style drawings, general web graphics
    • Windows application screenshots
    • When absolutely 100% quality is required (24 bit)
    • When alpha channel support is required
    • As a general replacement for anything that is a non-animated GIF
  • Bad:
    • Photos, in-game screenshots (only when quality is not important and you’re looking for small files)
    • Disappointing browser support from Microsoft and others
• GIF:
  • Good:
    • Where animations are absolutely required
    • Widespread browser support
  • Bad:
    • Patented, legal techicalities
    • Large file sizes compared to PNG for the same quality
    • Obsolete