Josh M. was a child that lived on the Federation colony of Omicron Theta during the early-to-mid 24th century.
He drew a picture of the colony being attacked by the Crystalline Entity that was later discovered by the crew of the USS Enterprise-D.
This painting was brought aboard the Enterprise. With the report of Lore, this artwork aided the starship's computer in its reconstruction of the entity. (TNG: "Datalore")