Another good rule of thumb is to look for one of these... © Even web sites that do not list the copyright symbol © and provide copyright information are protected.

Read more at What Is Copyright?

http://whatiscopyright.org/

Windows users usually right click on an image to save it to their hard drive. If you right click, and a warning window pops up, it is clear that the webmaster does not wish his or her material to be used elsewhere.

People also view source codes to accomplish this. Viewing source codes is a great way to learn, but stealing is nasty, no matter how it is accomplished. The best thing to do is just ask the webmaster. What can it hurt? The worse thing he or she can say is, "No". That's a lot better than getting sued. When thieves do get caught, the artist does not always sue. But there are those that do sue. Some even pay big money to watermark their images with tracking devices.

Nobody is a holy innocent when it comes to grabbing clipart. And yes, on the web, some will go for it no matter what, because the majority of people don't always get caught, and there is the type that questions,

"Why put it on the web if you don't want it stolen?"

Answer: "Why go outside when you could get mugged?"

LOL