Ask HI: Feedback on something we built . We call it 'The Google for Designers'

So we as designers were facing a problem - Searching for the right assets for any project was so difficult. Just to get the right image we'd have to search through 50 sites. So we talked to a few other designers and created a prototype search engine that collects and shows data from all major graphics websites.
It's called https://duper.app
Now we are struggling with finding the market fit. How do we validate (or invalidate) the product so that we can move on to the next iteration?