I have taken photos of photos on several occasions my 1st was a book cover photo I really admired. watch the light source (diffuse well) & watch for Parallax (thru the lens viewer is best) but you may be surprised how well this can work. Of course the largest photo will make better subject & ensure MAX quality of photo to reduce flaws. If digital use maximum pixels, if film, maximize depth of field.. DOC

I am 58 Y/O retired male RN in Texas who started in 35mm over 30 years ago. I've taken several serious classes & have many Rodeo & Western landscape photo credits thru the years.
The change to digital has been interesting but I really appreciate software alterations & tweaking without all the expensive darkroom equipment, It all still comes down to composure, action, & F-Stop/shutter speed to create the foundation needed for creating more than "Snapshots"
I am always looking for info that will improve my photos..
DOC