Introduction
You've made the perfect image for your web page in your favorite graphics program. You click "Save As", and you see something like the window below. Even the simplest graphics programs have a bewildering array of file formats you can save your file in. But which format is the right one?
First, relax. There's only three file formats that are used for regular graphics images on the web: GIF, JPEG, and PNG. So you can safely ignore most of the choices your graphics program gives you. Of the three, two of them are so similar (GIF and PNG) that you could ignore one of them and no harm done. That brings you down to two choices.
A lot of casual web builders adopt a rule of thumb: "Save everything as a JPEG" or "save everything as a GIF." Wrong! GIF is good for one kind of image and JPEG is good for another, and you'll almost never find an image that will do just as well in GIF and JPEG. You can ruin an image and waste hours of work if you make the wrong choice, and most of the time there's no way to undo the damage.
What you have to learn isn't hard, but you really do have to learn it to make successful files for the Web. So let's get started.