Linux users will want to use GIMP, which is 100% free. The GIMP is also a free option on Windows but is not the easiest program to learn. Windows users should consider the very affordable Ultimate Paint; many features are available without restriction even without the $39.95 (US) registration. Macintosh users and high-end graphics mavens swear by Photoshop.

Next, you must decide what file format to use for your images. Photographs should be saved in .jpg (JPEG) format when you are finished editing them and ready to use them on a web site. Most other images should be saved in .png or .gif format. Please do not ever use .bmp files on the web as they are very, very slow to download and do not work with some web browsers. Using .bmp format images can easily cause you to exceed your web hosting account's data transfer limit and incur additional fees!

For more information, see image file formats should I use?

Of course, not all graphics are made from scratch. Some are scanned from existing photos or printed documents; scanners are available for as little as $20-$40 (US). Others are uploaded from digital cameras, which can also be very inexpensive. Since most photographs on the web are 800x600 pixels or smaller, I suggest purchasing an older but well-reviewed digital camera. Clip art images are also available online; I recommend searching Google for the type of clip art you need. For instance, if you need images of cats, try a search for cat clip art. Unfortunately, the many clip art sites competing for your attention do not always actually have the images you need, and it can be difficult to locate images that are clearly free for you to use. Be sure to read the copyright statements on each clip art site and make sure you have a royalty-free right to use their images on your web pages. If in doubt, make your own.