I love this idea and would use it, don't listen to the naysayers. There have been previous attempts but that should only validate the need.

As a homeowner I would want this, and this would be useful to pretty much anyone looking for non-discount furniture (I say that because the IKEA demographic probably doesn't have time, money, or interest). I hated driving from furniture store to furniture store, and searching online would take many hours.

This would require a huge database of items. Maybe the vendors and manufacturers would give you photos to match against? make your vendors work for you if you can show that you could generate them business.

I think you are going to need some of the following consultants: furniture historian to help categorize older furniture, furniture designer to help sort into categories, a software developer to figure out how to match the image to a database, someone to work with manufacturers, and a lot of people to enter information.