This is an evil, evil, EVIL thread. I clicked the link, and now I've lost two days. I have completed Batch 1, 2 and 3 which means I've completed 50 puzzles. Batch 4 has to wait until tomorrow, because I'm afraid DH is about to divorce me over this.
Yes, 24 got me too. Just try anything you can think of for the first picture.
For 17...if you got this far, you have learned that keeping a record of your previous answers is very helpful. If you have kept that list, it will help you now.