If the guild has multiple words in it or has any spaces the code is a bit different, let's say for example the guild name is 'Colin Bryan' then this is what you put;
HTML Code:
<img src=profilelogo_Colin%032Bryan.jpeg height=* width=*>
Pretty much %032 goes where there's any spaces.
There may be another method of doing it and a more efficient one but that's the one I've always used and so far only one I know of that works.