The painting depicts the hand that holds the purple flag with a picture of a snake. The snake keeps in his mouth a flower.
דגל מחנה דן
The flag of the camp of Dan
Inscription in the frame:
כן חנו לדגליהם וכן נסעו (במדבר ב:לד)
So they camped by their standards, and so they set out (Numbers 2:34)