"That's My Weakness Now" is one of my favorite Bix-Whiteman recordings.
Here is a high resolution scan of the cover of the sheet music.
The art is by Albert Wilfred Barbelle, a highly prolific artist for covers of sheet music.
Bill Edwards has a fascinating account of Sheet Music Cover Art History in his website:
http://www.pritzkermilitary.org/search# ... &a=&y=&v=0
has lots of images of Barbelle's cover art.