Computer Related / converting .jpg

My goal is to change an folder icon, to a picture that I chose (obv. one in correct icon size)

So far, Ive learned (via google), that icons are .DLL

PShop doesn’t have a plug-in where you can save-as .DLL (as far as Im aware)

Id rather not use an image converter that reduces resolution as many do,
what are my options?

Cliffs :

• Make .JPG (or pic file) into a desktop icon
• Convert .JPG to .DLL via Photoshop plug-in
• Convert .JPG to .DLL via some sort of image converter

I know a bunch of you guys know some shit, so help if you can

Im pretty sure GIMP can do it

edit, that’s an .ico file might still work somehow

I think i found the plugin for CS4, so im all set- GIMP works well though

Icon’s are limited to .dll. They can also be .jpg, .ico, etc.

EDIT: Here is a link on how to do it in XP (possibly the newer Windows OS’s - I’ve never had to do it before) - http://www.raymond.cc/blog/archives/2007/05/07/how-to-change-the-standard-folder-icon-to-another-icon/