If you're having trouble with ImageShack (like I do) I suggest making Photobucket account. I just have less problems with it when it comes to Image sizes and multiple images.
1. Create Account.
2. Upload Images.
3. Mouse over the uploaded image or click share. Highlight the "thingy/URL?," copy and paste.
It should be like this [IMG]http://adsvndsomethingsomethingsomething[IMG].