Does anyone know the code for downloading picture? Like when someone click on the picture and there's this window open and it ask where to download (or something like that I think.)

could describe what you want a little more clearly im not sure what you mean :)

That sounds like a zip file. If that's what it is, then there isn't really a code for that - the person has to zip the file before they upload it. Then, when they want someone to be able to download the file, they can just link to it:

<a href="NAME.zip">click to download</a>

can you tell me how to zip it? like do we need a program or someting?

Yup, you need a program.

I use winzip (http://www.winzip.com), and there's a whole bunch at download.com (http://download.com.com/3120-20-0.html?qt=zip+files&tg=dl-2001&search=+Go%21+)