First, take the sides, top and bottom and cut to shape. Each end
of the items should be cut to a 45° angle so that when placed together, they result in a frame. Once cut to size, rout out a groove
on the inside (back) edge of each piece. This groove should be 1/2 in. wide and 1 1/4 in. deep (thus leaving a thickness of 1/2 in. remaining
from front to back). Note that hard maple is, like its name would suggest, a hardwood. Therefore, rout out this groove gradually, taking 
many
sweeps through with the router. If you are impatient and try to take too much off, you'll end up ruining a perfectly good router bit! At
this point, glue the four frame pieces together and clamp overnight. If desired, you can use very thin panel pins to nail the items together,
although wood glue alone should easily suffice.
While this outer frame is gluing, we will build the inner sub frame. This sub frame
is made out of edging wood (see diagram above) that is available at
Lowe's. As with the outer frame, cut the pieces to size with a 45°
miter. Plan before you cut so that the four pieces result in a frame.
This inner frame will sit under the main frame (see diagram below).
Note
that the exact size of these pieces should be the length of the space
available within the hole of the main frame, plus the measurement marked
as "X" on the edging piece (as this is the amount that the inner frame sits inside the outer one).
Once you have cut these items to size, clamp and glue overnight. Once dry, sand this inner frame and then paint it matte black to give a more subtle illusion of depth.
Have a piece 
of
glass cut to fit inside the outer frame and then place this in the frame.
On top of the glass, add the inner sub frame. Then, add the photo that
you want to use. Finally, add in the back sheet of plywood and use small
panel nails tacked into the inside back of the main frame to hold the
construction together. Finally, attach picture frame wire between two
small screws, one in the rear of each side piece, so that you have a means of hanging the picture.
