Ask HN: Where to Find Strength Training Exercise Libraries for use in Web App?

I'm building a web app to record users' strength training progress and I need to build an exercise database. Writing and using a scraper for this purpose would be highly illegal (right?), so I wanted to ask if anyone has specific recommendations on where to purchase workout/exercise libraries.

Ideally, they would be in an easily parsable format like CSV and have images to illustrate each exercise.