Ready

I finished the puzzle yesterday. It is the letter S in the Ultimate Alphabet by Mike Wilks. The painting has at least 1,234 different "things" of which a name starts with an S. (Sometimes Mike doesn't use common terms. In the Annotated Ultimate Alphabet all these "things" are numbered and listed, including the meaning.)
Funyn detail: his Signature has a wrong spelling, it is written Wike Milks.
The puzzle/painting, in fact all 26 of them, are a funny way to learn English words. But don't assume with the Ultimate Alphabet you will have all of them. Tons of words are missing.