I think I know what you're asking so here it goes. For the CD, you can search Google for an image of the CD case. When you find one you like, save it to your computer. I put mine at the root of my iTunes folder.

Next, in iTunes, select all of the songs that you want that CD pic applied to. You can select the songs by clicking on a song, hold the CTRL down, and then click on another song. Keep doing this until you've selected all of the songs for that album.

Then, right-click and select Get Info, click Yes to manage multiple items. On the next screen, put a checkmark by the artwork box, and then double-click on the blank artwork box.

You can then search for the CD image that you downloaded from Google earlier. Once you've selected it, click OK. The image should now show up for all of the songs you had selected.