General Graphics Tips

Here are some other things to consider when using graphics on your pages.

Programs that interpret web pages for the blind (either audibly or through braille displays) cannot read text that is in graphics. It is important that any text in graphics is also provided as alternate text so these programs have something to read.
Remember that fast moving text in animated graphics may be hard for people with cognitive disabilities to read.
People with low vision cannot change the default font or size of text in graphics, so they may not be able to read it as easily as ordinary text.
Animated images that flash could trigger epileptic seizures.
Be careful of "transparent gifs" where the background colour is designed to show through the image. Make sure this works with all background colours, not just white or black.
The "<img>" tag supports setting the width and height for images. However, in Netscape, if the alternate text cannot fit inside this width and height, then it isn't displayed at all, which is a problem for people who have images turned off. For small images, it may be better not to specify a width and a height.
The width and height attributes for images can be given in terms of percentage of the window size. This may be useful for adding pictures that adjust themselves to the available screen size. For example, a picture could always be 1/4 the width of the screen to guarantee text can fit beside it. This only works well with images that look good when scaled up or down.

Please send comments about this course to Kevin.Lowey@Usask.CA