Where? In RAM. It's an area of RAM set aside to use as temporary storage. You can put things in it by copying or cutting, and you can take tings from it (while still leaving them there) by pasting. There's no other access to it. There are no pictures - RAM is part of the big chip on the motherboard. (If you need to keep more than 1 thing at a time in storage like that, install something like
Clipper. But it's still only copy, cut or paste, just more than one item at a time.