Where do I store: background images, icon packs, and other theme files?

[ksaul]

I have a lot of background images that I want to potentially use on my Galaxy Nexus, but I can not find where they get stored.. I do not want them to show up in my Gallery - only shown when I am I trying to change the background image. Is this possible?

And like the title says, where do Icon packs get stored, and mClock and other theme files? I am new to the whole theming thing - so this might seem novice to even ask, but do I need a rooted phone to use icon packs and other themes? I installed Desktop VisualizeR and WidgetLocker LockScreen via the market but doesnt say anything about needing a rooted phone, right??

(i would like to install some of theses)

[ksaul]

anyone know if this is possible? i just want the icon images and background images not to show up in my gallery with the rest of my pictures - i only want the background images to show up in whatever folder the rest of the background images are in
and i only want the icons to show up whenever i startup desktop visualizer