Image markup/annotation

Hello!

I am wondering if there's some way to enable using annotation tools in a Canvas app so that the user can draw arrows and boxes around things on the image displayed in the Canvas App. Would it be potentially possible to use a free image markup site like annotely.com in an iFrame component? It doesn't require any authentication and has annotation features but doesn't appear to have an API so things like automatically loading an image into annotely don't appear to be possible.

Thanks in advance