Do the pictures on your walls have stories?
Write them on the backside.
One day in 100+ years, those pictures may end up at a thrift store.

I wish I knew the story of this crayon portrait purchased from Goodwill in Appleton, WI.
I have questions about those sad faces.
That must be intentional.
16x20 crayon portrait (c. 1900-1910 ish?)
Is this a photo that has been colored with crayon, or is it a painting done in crayon to look like a photo? -Phil
Called a Crayon Portrait which is colored pencils over early enlargements of photos. Depending on the person doing the coloring, some really look like photos until you look closely. https://www.picturerenewal.com/blog/photographys-first-enlargements
Crayon Portraits and the first enlargments

examples of restored crayon portraits and explanation of contact printing, crayon portraits and photographic enlargements.

Picture Renewal Photo Restoration