Proof that 'Exit Through The Gift Shop' is Hoax

There's a Banksy vimeo channel that features a video called 'B Movie' where Banksy is giving some insight into what he's doing. Check it:

B Movie - Exit Through The Gift Shop from Robin Gunningham on Vimeo.

Go to 3:56 when Banksy is explaining painting graffiti on oil paintings. You'll see him painting a gas mask on what looks like an old Victorian painting. THAT painting is featured in the "Mr. Brainwash" show toward the end of Exit Through The Gift Shop. In fact, the picture is shown two or three times, I believe.

I'm convinced that entire MBW show was all Banksy material. This clip certainly isn't undeniable proof (as the whole vimeo channel could be fake,) but I fell pretty sure that's the same picture.