Let's say you wanted to post idrivejunk's signature picture.

The URL for the image (which ends in .jpg) is "http://i807.photobucket.com/albums/yy358/chevroldsmobuiac/2016sig_zpsurmsjek6.jpg" (without the quotation marks)

to make it into a photo within a post, it would look like this (except without the spaces):

[img] http://i807.photobucket.com/albums/y...psurmsjek6.jpg [/img]

We take out the spaces and we get this image: