Use picture from keynote in another program?

This may be a weird question but I hope there is an easy solution that's staring me in the face.

I have a presentation in Keynote that I want to use the elements of for a presentation in another program (Prezi). I've managed to misplace my original file of one picture and after digging in the computer for a while, am wondering if there is a way to either locate the photo through Keynote, get info, get the name of the file...anything that will more easily allow me to track it down.

I tried copy and pasting but Prezi doesn't work with Keynote in that way.

Thanks!