This Life magazine photo, taken at Loiano, Italy in April 1945, is a closeup by internationally-famous photographer Margaret Bourke-White of the plexiglass grip of Lieutenant John Ernser’s .45 pistol containing a photo of his girlfriend. Ernser, age 26, was commanding an infantry platoon engaged in attacking fortified German positions.
The availability of acrylic plexiglass from the canopies of crashed or shot-down aircraft during WWII led to a common practice by American troops of replacing the original standard-issue grips on pistols or fighting knives with clear plexiglass replacements over photographs.
If you were not killing an enemy soldier with the modified weapon, you could stare at the image of your girlfriend and dream of home.
Below is a captured German trench knife (from my own collection) which has had its blade chromed and which has a girlfriend photo on one side, and two male photos on the other side.