where do downloaded files reside?

Hi! I upgraded to the Premium version and downloaded a file--specifically a *.jpg--from my computer (Windows--Vista) to my iPhone.

I can see/access the file (apparently on my iPhone) in the PocketCloud File Browser. Where does the file itself presently reside on my phone. I was hoping to transfer it from wherever it is now to iPhone's Photos--Albums--Camera Roll folder.

I guess I could always just email it to myself, but I was hoping to learn another (i.e., better) way.

Thank you!