Please tell me the price and the author
 

Good afternoon, tell me please whether there is value in these pictures.
Supposedly 18 th century, but the condition is very bad.
In the early 19 th century's great-grandfather kept them and I panyatiya do not have to do with them and where obraschatsya.

It seems to be viewed monogram "GP", "GB", and, possibly, "GR".
And the year "1888".
A more or less known artists with monograms, no one has found such writing.
Apparently, someone obscure.

Hence any value they do not represent