I would pay good money for a service where I upload a folder of images, gets an interface where I can classify each image one by one and then let ML classify the rest. Does this exist?
Interesting, we built a product similar to this and I'd be happy to have you try it out. Check it out here: http://symph-geoprocessing.appspot.com/ I don't think it has all the functions you are looking for yet, but we are happy to learn more about what specific features you are looking for and see if we can build them out.
Or you can use amazon mechanical turk to get everything classified by people
If you don't mind me asking, why do you want to do this?