Adding a thumbnail to each page...help?

[huge_nerd]

I looked at the mod page and tried to follow what the guy was saying but I still am unclear as to how i will call up that thumbnail in my template...i have been reading all teh tutorials and stuff and still am kinda cloudy. I added the
?thumbnail="icon.jpg" to the end of a link on the page but it is not indexing that link or soemthing...because it is not showing up or something...ugg..

http://www.phpdig.net/forum/showthread.php?t=279 ...that is the thread i was reading and what i was trying to do....

[huge_nerd]

what i have done so far is add the lines so the function_phpdig_form.php. And i was wondering what link do i add the ?thumbnail="filename.jpg" do i ad it to the link ont eh index page...like e.g. on the index page there is a navigation to other pages of the site...well would i add the thumbnail deal to the link or inside the actual page?