How do I upload images into the body shop?

In BodyShop when you go to the "Build Sims" screen, go to "package Sims". There you'll find two buttons, one for packaging Sims to send to friends or put on a website, the other is for sending them to the Showcase.

In terms of downloading things, when you download they will come in one of two types (at least until the game comes out and the methods may change.) If you download a zip file that contains a .package file, you put that directly into My Documents\EA GAMES\The Sims 2 Body Shop\downloads.

If you find a .sims2skins file (round icon with people in it), then you use it like an .exe file and it will self install. (Double click on the icon and you'll get a blue box saying "Do you want to install the following content?..." then hit "install". If it's not corrupted, then you'll get a second blue box saying "The Sims 2 Body Shop Content Installer---The custom content was successfully installed." If you don't get that message, you'll usually get one which tells you that there was a problem in the download. That means that you get to redownload it. (I have dialup and *frequently* get to "redownload" because the files get corrupted. It's a pain!)