Hi, I'm new to Windows Photo Gallery as you will see :)

I was editing some photos and I must have pressed a key erroneously because on the left side of my pics was a vertical sectional list of things that said, "downloads, iphone, all my pic folders with the dates on them.  What did I do? How do I get that back?

All I see now now for example is." July 2009" Heading with my pics then under "Aug 2009" Heading with pics,....I want to look at other folders.

Please help only if you don't laugh :)

Thanks