[pkscout]

I think that both have that.
Custom Search JSON/Atom API
The JSON/Atom Custom Search API lets you develop websites and applications to retrieve and display search results from Google Custom Search programmatically. With this API, you can use RESTful requests to get either web search or image search results in JSON or Atom format.

flickr.photos.search
Return a list of photos matching some criteria. Only photos visible to the calling user will be returned. To return private or semi-private photos, the caller must be authenticated with 'read' permissions, and have permission to view the photos. Unauthenticated calls will only return public photos.

Thanks for those. Here are my thoughts after spending some time with both. To set expectations, I believe AS should almost 100% of the time return the correct artist's images at a reasonable quality with an option to restrict them to 16x9 images.

With Flickr I can give you decent quality images and figure out the right aspect ratio, but there is no guarantee you will get an image of the actual artist. Meatloaf is my prime example. I did an API search with that, and none of the top 100 results were of the artist Meatloaf. They were of, well, meatloaf. Even using Billy Joel, most of the first 100 results were crappy, low quality images. Given that, Flickr is out in my opinion.

With Google, I would have to get an API key using my personal account at which point it would be limited to 100 queries per day with additional queries costing $5/1000 queries. That's a deal breaker. I'm not going to have AS use an API that can only do 100 global queries per day, and I'm not spending $5/1000 to buy queries. I suspect Google is going to give similarly crappy results (as far as AS is concerned), so that one is also out.

Folks, seriously, if every one that used AS gave $2 a month ($1 to theaudiodb and $1 to fanart.tv), this problem of availability would be solved many times over. So again I beg you to please pay to support the high quality sites that make AS possible.