Signatures are coded from runescape.com or entered by the user. You could make a site with the stats of players but it could only be done by getting them from runescape.com.
Example: Making a website to obtain the users stats From Runescape.com and have it visable at your site.
There is no other way to keep uptodate stats then looking at
http://www.runescape.com highscores!
OR
Make a runescape client in VB, C/C++, delphi to get the stats of the current user logged into the client.
Many dont use game clients that arnt from the offical website/team because they have keyloggers.
-
To make a site to obtain the stats you would need to learn, HTML, PHP, Javascript. I think atleast one of those.
And yes, images can be coded:P
EDIT:
What i mean by looking is having the code direct to
http://www.runescape.com highscore Username.