Pros and Cons of WebMountable Image Formats

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Pros and Cons of Web-Mountable Image Formats
Presentation by Serena Wakefield with nature
photography by Rachel David (used with permission)
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Web-Mountable Images

• One of the strengths of the Web is the ability
  to publish illustrated documents that can be read
  with a wide variety of software. When publishing
  images, selecting the proper graphics format is
  vital to ensure that your reader gets the full
  experience of the content youre providing.

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The GIF

• The Graphics Interchange Format, or GIF, was
  popularized by Compuserve. It is one of the most
  popular graphics formats because of its
  versatility and because of its special features
  and options.

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The GIF Pros

• Virtually all web browsers support GIFs.
• A built-in transparency effect allows GIFs to be
  seamlessly integrated with text and background.
• A built-in animation feature makes for colorful
  and interesting presentations.
• A built-in interlacing feature allows
  slow-loading images to fade in, so the reader
  can see what the image is going to be while its
  still loading.

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The GIF Cons

• GIFs are limited to 256 colors, making them less
  suitable for photographs.
• Some older browsers wont display newer GIFs in
  the correct colors.
• The GIF uses a patented type of compression, and
  you may need to license it from Unisys to use it.

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The JPEG

• Probably the most common format for photographic
  images is one developed by the Joint Photographic
  Experts Group the JPEG, sometimes further
  abbreviated to JPG. The JPEG provides you with
  all the colors you need to display photographs,
  but its not a perfect format.

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The JPEG Pros

• Virtually all web browsers support JPEGs.
• JPEGs can have up to 16 million colors, so you
  can display photographs better than with GIFs.
• JPEGs have compression, keeping their file sizes
  down you control how compressed the file will
  be.
• Progressive JPEGs fade in images much like
  interlaced GIFs.
• JPEG is absolutely free to use.

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The JPG Cons

• JPEGs can be blurry, as some of the detail in the
  image is sacrificed during compression to keep
  the file size down.
• JPEGs accumulate artifacts, splotches of the
  wrong color in high-contrast areas.
• Progressive JPEGs only work well with very low
  compression.
• JPEGs dont have animation or transparency
  features.

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The PNG

• The Portable Network Graphic is a new format
  intended to replace the GIF and, to a lesser
  extent, the JPEG. The format is useful and
  versatile, and has many of the strengths of both
  of the other formats.

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The PNG Pros

• PNG has the special transparency and interlacing
  features of GIFs, but produces better results
  when displayed on a website.
• PNGs can have more colors than JPEGs, making
  photographs look close to perfect.
• PNGs look like theyre supposed to on any
  computer.
• PNGs are lossless, meaning the image comes
  through exactly as it was intended.
• PNG is absolutely free to use.

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The PNG Cons

• Not all browsers support PNG, and some of those
  that do dont display them correctly.
• While PNGs are usually smaller than comparable
  GIFs, they tend to be MUCH larger than comparable
  JPEGs
• PNG displays more slowly than any other major
  format except BMPs.
• PNG may be more powerful, but its additional
  expert-level features make PNGs more difficult to
  create than either GIFs or JPEGs.

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The BMP

• The most basic form of image on Windows systems
  is the Bitmap, or BMP. Bitmaps are versatile and
  powerful, but can be difficult to use they only
  barely qualify as a web-mountable graphics
  format.

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The BMP Pros

• BMPs can have an incredible variety of different
  colors.
• BMPs are sharp and clear basically, they can use
  the readers monitor resources to the fullest.
• Virtually any image editor can work with BMPs.

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The BMP Cons

• You cant display BMPs in most web browsers
  without much more work.
• BMPs tend to be larger than other image formats
  sometimes up to ten times larger because they
  do not compress the image.
• BMPs display more slowly than any other major
  format.

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Other Popular Formats

• The TIFF format, while ideal for archive
  photographs, cant be displayed by most browsers
  and thus does not count as web-mountable.
• The PCX format was created by ZSoft for its PC
  Paintbrush software. While once very popular, it
  is now obsolete, and most browsers do not support
  it.
• The SVG, or Scalable Vector Graphics format, is
  still in development, but is intended to rival
  PNG for versatility.
• MNG is a new format for animated graphics
  developed by the creators of PNG however, most
  browsers do not yet support it at all.

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Bibliography and Further Reading

• California Digital Library Digital Image Format
  Standards. http//www.anybrowser.org/campaign/
• Choosing the Right Format For Your Web Images.
  http//tech.irt.org/articles/js206/
• Image File Formats TIF, JPG, PNG, GIF.
  http//www.scantips.com/basics09.html
• Image Formats on the Web. http//www.htmlgoodies.
  com/tutors/image_formats.html
• Image Formats. http//www.yourhtmlsource.com/imag
  es/fileformats.html
• Viewable With Any Browser Campaign.
  http//www.anybrowser.org/campaign/
• When and How to Use Internet Image Formats.
  http//www.r1ch.net/img-formats/
• WDVL Graphics Formats for the World Wide Web.
  http//www.wdvl.com/Graphics/Formats/

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More about Specific Formats

• Unisys Statement to Press and On-Line Community.
  http//lpf.ai.mit.edu/Patents/Gif/unisys.html
• JPEG FAQ Index. http//www.faqs.org/faqs/jpeg-faq
  /
• Portable Network Graphics. http//www.libpng.org/
  pub/png/
• The Unofficial TIFF Home Page.
  http//home.earthlink.net/ritter/tiff/
• TIFF Format Support and Development.
  http//www.adobe.com/support/salesdocs/2596.htm