My attempts to find through USHMM things I found in the Arolsen Archives fail.
The link to Arolsen Archives online is: https://collections.arolsen-archives.org/en/search/ 
It takes getting used to the interface, 

If you find an image, you should: 1) click on the square that lets you see the image in its original size (see attached image), and then, 2) depending on your browser you can download it, or (if using Google Chrome) right click on it and ask to view it in a separate tab).
You can also move it about in the small viewing frame (an option I don't really like).
Make sure to ask for the original size first.