plus that is just the URL by itself. at a minimum you would have to put the image tags on either side of it with no spaces in between. [img]before_the_URL_text_and[/img] after the URL text.
But it still looks too big to me:
Actually it looks like you have hosted it at photobucket, so if you have an image editing software program that works with .png file formats, you should be able to adjust it to be thinner. If you don't, do a search of irfanview software. It's freeware that you can download and install to do these kinds of operations.