Like many developers, I'm pretty confused on why Google deprecated so many of its APIs (Images, Translate etc). Does anyone know of a good alternative image API that is somewhat accurate? Flickr seems pretty inaccurate in my testing : /
It really depends what you're looking for. The major alternatives out there are Yahoo's Boss API, Bing's Image Search API, and Flickr's API which you mentioned.
Bing and Yahoo both have larger amounts of images than Flickr.
Flickr is more lenient in terms of what you can actually do with the images however. Both Bing and Yahoo limit what you can do. For example, Bing doesn't allow you to reorder your search results and Yahoo has a hard-limit on the number of requests you can make. Flickr allows you to do basically anything as long as you don't spam requests or abuse their user's rights to the images.
Bing also tends to have the more detailed search engine, as you can search for different colors, and categories than Yahoo or Flickr.
In the end, I'd advise reading over their respective Terms of Services(Flickr, Bing, Yahoo), and using the one that fits what project you have in mind.
I hope this helps, and good luck!