How to find name of original image name in PowerPoint?

I found an old PowerPoint slide I made, but I really want to find the original image that I imported to the slide. Is there a way to find the name of the image, upon which the slide is based (e.g., I inserted 'imageFoo.jpg' into my slide). I'm sure it's in one of my hard drives.

I have tried exploring the properties of the image (right click, format image), but the closest I got to the original is its size property. Googling didn't reveal the answer.