Image is flipped from its original printing in Tom and Jerry Comics (Dell, 1949 Series) #146 (September 1956) and its prior reprinting in Tom and Jerry (Western, 1962 Series) #236 (June 1967) which had Tom facing right, to Tom facing left - with all illustration elements flipped accordingly.
This was most likely done to accommodate the UPC code box, which would have interfered with Jerry and Tuffy's fishing lines as previously rendered. Tom's fishing line is also shortened for the same reason resulting in a change in perspective.
The separation of the water and sky (now more garishly colored) is now delineated with a black inked line, where in the previous printings water and sky simply "blended into one another".
Tom enacts a particularly cruel and unusual punishment on the mice in the story's final panel - forcing them to eat a grindstone (painted to look like a wheel of cheese) by chiseling it down piece by piece.
JERRY: But, Tom, we can't eat THIS!
TOM: It may take A LONG TIME, but you can do it!