It takes anywhere from about two (for a tiny piece of clip art) to twelve or more hours (for a set based on a small watercolour painting) for me to create the original drawings that my graphics are based on. From there, in order to make a set, it would take several more hours of fiddling around to do the border background, the buttons, the bullets and dividers. I enjoy it most of the time, though sometimes it can be frustrating.
If you take my base pay for my regular job, that's up to about $240 per set. Now, I realize that people can't afford to pay that kind of money for a graphics set for a personal web page. I'd love to have the money but it just isn't realistic. So most of my sets are what is called Linkware. You find a graphic you like, you copy it to your own hard drive and upload it onto your own server. You give me credit on the same page as the graphic and a link back the same day the graphic is first shown on your page and we're both happy. Other people who are making web pages and like those pictures can then come and have a look at my graphics, and hopefully find one that suits their needs too.
If you don't give me credit, then you have stolen my work. I have occasionally found a picture or two of mine online without any credit given. It's flattering to see that someone liked my work, but I don't appreciate finding that it has been stolen from me. I'll usually send a note asking for the appropriate credit. But don't let me catch you with my graphics in your free graphics collection.
To explain the differences between these scenarios to you, let me make it into a sort of analogy. Suppose that I invite you over to my house, and I bake some special cookies for the occasion. The guest who comes over, and sits down to tea with me and waits to be offered the cookies is like the person who finds my graphics, likes them, and uses them while giving me credit for it. The person who is invited over, and immediately searches through my cupboards and helps themselves to my cookies is like the person who likes my graphics and uses them to decorate their pages without giving me credit for them. The person who is having company over, so they sneak into my house and steal my cookies so that they can give them to their own guests is like the person who takes my graphics and puts them into their own free graphics collection. Guess which one I'm most likely to sue? I'm sure you can understand why this is an unsettling thing for an artist. If you steal my graphics, I have been violated in the same way you would feel if you came home and discovered that someone had broken into your house and stolen from you, and then had the nerve to advertise your things for sale in the newspaper. I'm not even going to get into discovering that someone has stolen my graphics and is altering them and charging other people for the results!
I'd like to add that putting graphics you have neither the copyright to or permission to use and then just putting up a disclaimer like "I don't know who the artists are. If you know, please tell me, or if you own the copyright and ask me I'll take it down" does not alter the fact that you are breaking the law. In fact, if you do that you're admitting that you know that what you're doing is wrong, and you didn't bother to check around to get permission.
Sure, it is tempting to scan a picture you like and put it up on your web pages. Many of us can't draw or paint as well as so-and-so (myself included) and we know our pages would look so much better with their pictures on them. Well, I feel the same way too. I'm a huge fan of Leighton, Waterhouse, da Vinci, Michelangelo, and numerous other painters who are so much better than me that my pictures look like stick figures beside theirs. And I was soooo tempted to use their stuff on my web pages when I first started out. Even now, I see people with absolutely mouth-watering background sets in their free graphics collections and I want to use those backgrounds on my pages. But they're based on paintings that the person didn't have the right to use and if I use them I'm breaking the law. So I draw and paint my own stuff and use it instead. It isn't as good, but it's the right thing to do. If you can't draw and paint, there are resources like my free graphics, and many, many other pages by artists that you can use. Just be careful to use sets made by the original artist; otherwise you might be breaking copyright laws without realizing it.
If you're having a hard time finding something you like, do a net search. Here's a good page for horse and dog lovers:
Doris' animal graphics links
There are other pages which better describe the idea of copyright