The photo of Molly that Ben shoves into the mailbox is wallet-size (it was in the stolen wallet), maybe 3" long, judging by the size of his hand holding it. However, when he passes the mailbox later, the photo that pops out is at least an 8 x10" (judging by the size of a standard USPS mailbox) when the frame is frozen. Then, when he picks it up, it is almost 6" long, as big as his entire hand, and more suitable to a frame on a desk. The same photo is three different sizes. Is the mailbox magical?
When the painter was drawing the Chinese woman using soy sauce, he dripped a few drops on her face, but in the next scene, in his studio, the soy sauce drips are gone.
Molly is shown having her photograph taken by a photo booth situated inside a pocket park. There are no such structures, outside, in New York City. Perhaps there were, up until the 60s, but only in a couple of high foot traffic areas, like Times Square or Coney Island.