What permissions have I given when using certain applications?

I just logged on to facebook, and they let me know they took some of the pictures I snapped recently and made a nice slideshow with them.

These are not pictures I uploaded to facebook. They seemingly went into my photo folder on my phone and selected the latest ones. This was done as a service to me.

Now, I am wondering who can see what of my private pictures.

I know there is safety in numbers and I am not special enough for anyone to be bothered, I guess. But, have I given a facebook employee the right to browse my pics? (i know the collage was put together by a program).