Where are all the hidden drawings in Cut The Rope?

There are 19 hidden Om Nom drawings in Cut The Rope game (for both iOS and Android). Where are they found?

Related question: Where are all the pictures in Professor's Album in Cut the rope: Experiments?

All drawings with numbers

Drawing #1

Go to the Album and click on the grayed out piece of paper with the large Facebook logo. Click on "Like" to be redirected to the official Cut the Rope Facebook page. "Like" them if you wish, then return to the app to see your new drawing!
Video Walkthrough

Drawing #2 Cardboard Box Level 1-16

Go to level 1-16 in the Cardboard Box to find the drawing in the bottom-right corner, under the message which explains that spikes are bad.
Video Walkthrough

Drawing #3 Fabric Box Level 2-18

Go to level 2-18 in the Fabric Box. The drawing is hidden at the bottom of the level, to the left of Om Nom and right of the third star. You will have to play your way past the spiders to reach it.
Video Walkthrough

Drawing #4 Foil Box Level 3-3

Go to level 3-3 in the Foil Box to find the drawing below and slightly right of the candy's initial position. Don't be swayed by the huge rip on the left side of the screen!
Video Walkthrough

Drawing #5 Foil Box Level 3-20

Go to level 3-20 in the Foil Box to find the drawing directly above the candy's initial position.
Video Walkthrough

Drawing #6 Gift Box Level 7-14

Go to level 7-14 in the Gift Box to find the drawing directly above the rightmost air cannon in the bottom row, next to the two lower stars.
Video Walkthrough

Drawing #7 Cosmic Box Level 8-1

Go to level 8-1 in the Cosmic Box to find the drawing directly above the spikes over Om Nom's head.
Video Walkthrough

Drawing #8 Cosmic Box Level 8-15

Go to level 8-15 in the Cosmic Box to find the drawing above and to the right of the rightmost star. You may need to push the candy rightward with the air cannon to get the drawing properly in the screen.
Video Walkthrough

Drawing #9 Valentine Box Level 5-7

Go to level 5-7 in the Valentine Box to find the drawing below and to the right of Om Nom, next to the right half of the separated candy.
Video Walkthrough

Drawing #10 Magic Box Level 4-3

Go to level 4-3 in the Magic Box to find the drawing behind the leftmost magic hat. Unfortunately, there is no rabbit to find in the hat, only a well-drawn picture of Om Nom.
Video Walkthrough

Drawing #11 Magic Box Level 4-21

Go to level 4-21 in the Magic Box to find the drawing immediately to the right (or left) of Om Nom.
Video Walkthrough

Drawing #12 Toy Box Level 6-17

Go to level 6-17 in the Toy Box to find the drawing below and to the left of the leftmost peg.
Video Walkthrough

Drawing #13 Toolbox Level 9-21

In level 9-21 in the Toolbox to find the drawing immediately below Om Nom, just above the topmost star.
Video Walkthrough

Drawing #14 Buzz Box Level 10-15

Head over to level 10-15 in the Buzz Box to find the drawing in the top-left corner of the level. For reference, it is two honeycombs above the topmost star.
Video Walkthrough

Drawing #15 DJ Box Level 11-16

Go to level 11-16 in the DJ Box to find the drawing to the left of Om Nom, at the edge of the screen.
Video Walkthrough

Drawing #16 Spooky Box Level 12-14

Go to level 12-14 in the Spooky Box to find the drawing at the top left edge of the screen.
Video Walkthrough

Drawing #17 Steam Box Level 13-9

Go to level 13-9 in the Steam Box to find the drawing to the left of Om Nom, at the edge of the screen.
Video Walkthrough

Drawing #18 Lantern Box Level 14-13

Go to level 14-13 in the Lantern Box to find the drawing to the left of Om Nom, at the edge of the screen.
Video Walkthrough

Drawing #19 Cheese Box Level 15-13

Go to level 15-13 in the Cheese Box to find the drawing to the left of Om Nom, at the edge of the screen.
Video Walkthrough

Source: http://www.rocketpond.com/cuttherope/cut-the-rope-drawings-complete-guide/