i know it may seem like a pain in the ass to most programmers, but i have always used the complete address whenever calling a function or linking a picture
Code:
http://www.myserver.com/pic_directory/pic.jpg
it just makes more sense, it's more portable (you can move it from one server to another, just changing the name of the server using Find&Replace in any editor) and it leads to fewer problems. the only time i won't use the complete address is when the pic or link is in the exact same directory and it will always be like that.
cutting corners is not the same as a shortcut...