Q:

Masking image on Shape

I have a photo, and on it, I have drawn a circle with a shape. 
I want to make it so that only the parts of the photo that are within this circle are visible, and what is outside the circle should not be visible. Therefore, I should be able to position the image with part of it in the circle and end up with an image that is the shape of the circle. 

A:

Layer -> New Clipping Mask
Place image above the shape and apply the above. 

