Remove the 4 screws holding the front glass in place. Take the battery out to move the second hand away from where you want to fasten your photo. Also, use the knob on the back of the clock to move the hour and minute pointers out of the way of where you want to attach your photo. Using 'blue tack', double sided sticky tape, or similar, attach your photos to the face of the clock behind the pointers. Replace the glass, on which the numerals or dots are printed, so they are now in front of your photos.

photo Clock, plastic case, with dots