I think you should be able to e-mail the person or contact them and tell them how much you like the image and ask them can you "have"/use it! If they give their permission, that's great! The biggest thing with using images on the Web and copyright laws is that you have to be making money where you use the image. If you "borrow" (steal :-) someone's image for your site and it's making money for you because people see/like it and shop on your site, etc. and the owner can show it is clearly theirs; they will ask/tell you to take the image down/off your site. If you don't, they can sue you and probably win so you'll be forced by law to take it down. The big businesses (especially Disney and other cartoon sites, etc.) have to do that often. But a lot of images are so often used and never challenged that no one knows anymore whose they are. It's just polite though to ask someone if you can use their image.

And it's never a good idea to just take the link to an image and post that as that is "bandwidth theft". People who own sites have to pay for the "space" they use and the more or larger images and neat stuff, the more espensive the site is for them. In addition though, they're usually charged depending on how many visitors they have to their site so, using their link to their site means wherever you post it, people will literally be referenced to their site to see it but the owner won't get traffic to the whole site, just the use of that picture which people won't know is from another site! So the owner gets charged for all those people looking at "his" picture but doesn't get any benefit of people actually being at his site and doesn't even know where the picture is being referenced.

Usually though if you're just downloading a picture you find on the Web to your Photobucket account because you really like the picture and enjoy looking at it yourself, etc. I do that sort of thing sometimes without asking and don't feel too guilty :-) I get funny e-mail pictures/cartoons from friends/my sister-in-law and I save them to my machine and send some on to other people or post them, etc. sometimes. It gets very hard to know where something comes from sometimes and who to ask, etc.