Here is my page on cats. I have three brown kittens and a mean old tomcat. They all live under my bed.
Notice that all of the pictures on this "page" are of birds, yet birds are not mentioned in the text. Don't place pictures on your site just because you can; only put them where they are relevant. This page could be improved by having one or two small pictures of cats, preferably this person's cat.
Did you notice how long this picture took to load? That's because it was not compressed. Most pictures that you find online are JPEGs or GIFs, which are compressed and very good for the Internet. However, the picture above is a bitmap. Since bitmaps are uncompressed and very large, the picture above is 161 kilobytes. If it were saved as a JPEG, it would have been about 1/10th of that size. All pictures that you put on your site should be either JPEGs or GIFs.
One feature that many people are interested in using is animation. Animation is often used on webpages and sometimes even enhances the image. However, most of the time, it is just annoying. Have a look at this Flash animation:
It is pointless, annoying, and takes a long time to load. You're probably even distracted as you are reading this text. The only way it could be improved is deletion. In general, when considering animation, consider only leaving it out.
What is the difference between these two words? Well, if you have a dial-up connection you probably noticed that the one on the left took a while to load. That is because it is a picture. There are only two reasons to ever make text a picture. If you are creating a menu such as the one on the left side of this page, it will need to be an image. Also, if you are creating your page in a English and a language such as Hebrew, that requires a separate character set, it is okay to make your text into JPEG files. In any other situation, including the use of a "cool" font, it is a waste of time and bandwidth downloading that extra picture. Stick with text.