Continuity mistake: When Joan is doing some sewing on her yellow dress, you can see that the ball of wool in the sewing basket next to her has nothing in it. But when Jerry puts one of the photographs inside the dress, two knitting needles have appeared. The needles then disappear in the next shot.
Continuity mistake: When we see a close up of the photo that Jerry has taken, look at the rug that Spike is lying on. You can see that it is completely different to the one when Jerry was taking a photo of Tom putting a chicken under Spike's arm earlier in the short.