I could do these types of puzzles all day. Below are two images by Hungarian illustrator Gergely Dudás, who has changed five elements from one to the other. Anyone with design training ought be able to solve this quickly, (though I'm ashamed to admit that while I spotted the first three quickly, the final two took me forever). Have a go:

Larger:

Scroll down for answers:

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I bet the sequence in which we spot the differences says something about the way our brains are wired. My sequence was:

1. Pumpkin/s sign, immediately. (Proofreading background, my eyes instinctively go to text first when assessing an image.)

2. Hatband on the pilgrim bird. (Color switch easy to spot.)

3. Color switch on pumpkin at lower left. (Color switch easy to spot.)

4. Crack in board at joint. (Took a long time.)

5. Missing pumpkin stem at lower right. (Took forever.)

So my sequence was text, color, form. What was yours?