You'll find that Zelda Dungeon is nicer than Zelda universe. Well, the users, that is. Plus, at ZD we don't believe in ignoring newer members as many other forums have. You'll find that we have a rather large welcoming party.
Photoshop is an image editing program, photobucket is a free online image host.
As for your problem, I've found it.
http://img87.imageshack.us/i/picture844.png/ - This is what I was talking about when I said some users had problem with imageshack. When I said .png or .jpg I meant strictly that and nothing else, which means the / at the end of the URL is what is throwing it off. If you copy/paste that link into your browser you should be taken to the imageshack page. In the bottom right click "Link to share this image". Make sure you copy the direct link, and not the one that simply says "link". Copy and paste that url into image tags.
It may be that you are using an incorrect link. If you are using a website such as imageshack to upload images then that may be the source of your problem. A lot of users who use imageshack copy the first URL they see in the information instead of the direct link. The direct link to an image should always end in .png, .jpg, etc. and nothing else. Make sure you're copying the correct link and wrap it in the image tags. If you're still having problems I would suggest a website such as photobucket to upload images.