For a full page photo the image should be cropped to the same size ratio as the page, i.e. 8.5:11 or 1:1.3. When the photo is added to the full page layout it should fit into the frame without any cropping. Most other frames are in the 4:3 size ratio which is about the same: 1:1.33.
Or you can Command (right) - click on the image on the page and select Fit Photo to Frame from the contextual menu. This will shrink the photo until it if fully presented in the frame without cropping but will not be edge to edge.
The following is an image from an iPhone with the size ration 1.338 in a full page layout:
This is after fitting the photo to the frame:
If the page background is set to black the two areas at the top and bottom won't be that obvious. It all depends on what's in the photo, however.
OT