Another option that can be used if you want to offer a lot of imagery is to provide thumbnails that link to larger versions of the image. Let's suppose that I want to offer three very nice pictures of let's say a few of my cars (I wish).
Click on the thumbnail to see a larger image
The first thing you need to do is fire up your image editor and make smaller versions of your images. It would also help to reduce the color depth. This bit about making a smaller version is very important. I have seen many instances of someone trying to make a thumbnail by simply reducing its dimensions in the <IMG> tag. All this does is cram the full image into a smaller space. What you need to do is create a smaller copy of the image and use that as a link to the big image.
Let's do one. I think we'll use the Corvette (that's the blue one if there's anyone out there that for some silly reason doesn't know). Put the full sized image and the small image in your working folder. Once again... right-click & Save Picture As. (or something similar)
Joke Break