Also don't forget that many people turn off the display of graphics for just this reason. So they'll see you page, but without the pictures. If your pages take longer, take out or redo the graphics to make the loading of each page faster. Graphics load more quickly if they contain a small number of colors. Limit the colors to the 16-color palette used by Windows' PaintBrush.
Interlaced graphics can keep the viewer interested while the browser transfers the graphic.
Interlaced graphics display as they load, typically with resolution going from low to high. Many graphic programs can create interlaced graphics. Use the same graphic on multiple pages. Besides consistency, there is a technical reason for this. The first time the graphic needs to display, it is downloaded to the user's computer and held in the browser's cache.