Laughing Cat Studios - Web Design and eCommerce

Image Basics for Web Design

Images for Web Design

need to be in one of three formats. Here we list some notable differences in the .gif, .jpg and .png formats.

 

Web Design AnimatedGIF (Graphical Interchange Format)

  • Best used for vector graphics, line art.  Not Photos.
  • GIF89a format provided enhancements for transparency, interlacing and multi-frame GIFs for animation.
  • Limited to 256 Colors
  • Compression format is lossless compression format – Which means no image information is lost when compressed.

Web Design with jpg
JPG (Joint Photographic Experts Group)

  • Best used for photographs
  • Unsuitable for images with sharp edges, such as line art, logos and type
  • Compression format is a lossy compression algorithm which means that file information is lost when compressed.  Therefore, wait until all modifications are made to save and compress your jpg files.
  • Each time a jpg is saved/compressed, file information is lost.
  • jpg does not support transparency.

Web Design with png
PNG (Portable Network Graphics)

  • Created to improve and replace GIF
  • Compression format is lossless compression format – Which means no image information is lost when compressed.
  • Better transparency than GIF files
  • Does not support animation
  • Supports palette-based, true color and grayscale images

Interesting History: The motivation for creating the PNG format was in early 1995, after it became known that the Lempel–Ziv–Welch (LZW) data compression algorithm used in the Graphics Interchange Format (GIF) format was patented by Unisys.

On December 24, 1994, Unisys stated that they expected all major commercial on-line information services companies employing the LZW patent to license the technology from Unisys at a reasonable rate, but that they would not require fees to be paid, for non-commercial, non-profit GIF-based applications, including those for use on the on-line services.

Following this announcement, there was widespread condemnation of CompuServe and Unisys, and many software developers threatened to stop using the GIF format. The PNG format was developed in 1995 as an intended replacement.  Unisys was subjected to thousands of online attacks and abusive emails from users believing that they were going to be charged or sued for using GIFs on their websites.  Despite giving free licenses to hundreds of non-profit organizations, schools and governments, Unisys was completely unable to generate any good publicity and continued to be condemned by individuals and organizations such as the League for Programming Freedom who started the “Burn All GIFs” campaign.

The US LZW patent expired on June 20, 2003.  Consequently, while Unisys has further patents and patent applications relating to improvements to the LZW technique, the GIF format may now be used freely.

December 28, 2010   No Comments