Global Attributes Global attributes such as backgrounds, text colors, and so on are not to be specified by individual pages. Standard values, if any, are specified in the standard header. Do not exceed 80 columns. Don't use unusual characters that aren't portable. Just avoid characters that need to be typed using a command, option, alt, or meta key.
Images When using images, consider the cost to viewers with slow connections.
Large images increase transmission time. Large numbers of images, even if small, also increase loading time. Images can be in either GIF or JPEG format. In general, new innovations must be avoided if departmental pages are to reach a wide audience. This includes such things as frames and Java applets.