It can save you a lot of hassle, embarrassment and possibly money. 10 Big Myths about copyright explained . It is also very important to read the Agreement for your web space provider. Some of them state that all materials placed on their server becomes their property. If you put graphics that do not belong to you on these servers, you could be liable to the artist for giving away rights that do not belong to you.
Some graphics are public domain and can be used freely anywhere.
You will find these on the larger sites like The Clip Art Connection, NetCreators and The ClipArt Castle. Some artists will let you use their graphics on those servers too. Just use caution and common sense. When you get permission to use an artist's work on a free site, always keep the message and back it up. It's not a bad idea to check the server's rules occasionally.