The Yale Center for British Art has done a wonderful job of making virtually its entire collection available online, and unlike most online images of paintings they include the frames. There is a dedicated frame search page, and it's a great resource for framers interested in historical styles and designs. Here is the full list:
An example of how useful it is to have frame images reproduced online is this British 18th Century frame that I have, with a very fine example above it seen in the Yale archive. This frame is clearly the same, probably by the same maker, and the images of the complete example would make it much easier to restore this frame to an original condition. It is not a particularly common design so a reference image and some information is invaluable.
