Help posting photos with a Mac

I found this on my own an the WEB. The exact address is www.shrinkpictures.com. I will not go to the Mac store till today. My Mac is 8 years old and Apple will not talk to me unless I pay$. I am planing on getting a new one in the near future when i get some financial issues settled, will then sign up for the classes as I will have a whole new set of things to learn. The official Apple store is over an hour away, but we have an authorized dealer fairly near and they are extremely helpful with my very old mac, it frequently has one issue or another but I love it and won't go back to a PC.
They have a option to size a photo for an avitar, tried that and got back a completely black picture, don't know what that is about .