You can't get raw texture rips as the ones in game are pre-rendered static images (called CAMs) with certain parts being redrawn over the top (FG1 layer as it's known) of all other sprites to simulate the idea of it having depth.
The best you can do is cut parts of the backgrounds out from their CAM or other images. To do this, you should use the Decoder app which Paul made in order to extract these files
found at his website here.
After downloading it, tell it where your installing AO or AE directory is and extract the images, and then you can take whatever bits you want from the BMP files (bearing in mind their resolution is lower than the game is actually displayed; they're scaled up) using a normal image editing program.
You may also find
this thread helpful, as it already has some of the background stuff cut out for you in PNG format.