• Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint
Share this Page URL
Help

Lesson 2. Working with Graphics > Placing Graphics on the Page

Placing Graphics on the Page

The most common and widely supported graphic formats on the Web are GIF and JPEG. In general, use GIF if the artwork has large areas of solid colors and no blending of colors, and use JPEG for photographic images or images with a large tonal range. A picture of blue sky with clouds, for example, looks posterized when it is saved as a GIF image. All the different shades of blue are mapped to only a few colors. GIF images are saved, at maximum, in 8-bit color mode, which means that only 256 colors can be represented. Browsers display only 216 colors, which makes the problem even worse. JPEG saves the image in 24-bit mode, retaining all the colors and using a lossy form of compression in which redundant data is lost. The lower the quality of a JPEG, the more information is lost about the image through this discard of data. GIF files tend to load faster, have more optimization options, and support transparency and animation. If you are working with a graphic that can be saved as either GIF or JPEG, choose GIF whenever possible.

Interlacing is a method of defining the way the image is displayed in the browser. Interlacing displays every other pixel in every other line and then goes back and repeats the process, filling in areas that are not already displayed. Without interlacing, the graphic is “painted” on the screen line by line, starting at the top of the image. Interlacing adds slightly to the file size and download time, but it gives a visual clue that something is happening.


PREVIEW

                                                                          

Not a subscriber?

Start A Free Trial


  
  • Creative Edge
  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint