Photos have been "Painted" since the 1840's. Additionally the actual surface texture of the photo "paper" could have been glossy, matt, luster, canvas or watercolor paper. Almost any medium can be used;oil, watercolor pigments, pastels. If the surface of the image FEELs thick and smooth (think oil paint on wood trim) it is probably an oil paint (no glass) any other effect is best under glass. The only catch 22 might be that it has a Matt attached to the already mounted (on foamcore) print. The addition of the matt necessitates glass...eventually the matt will absorb water moisture and buckle off. Ask the person who gave it to you, how it was created.