The History of Dot Pictures
Joining numbered dots to make a picture is an old puzzle form from children's books and puzzle pages.
Dots as a guide
Dotted lines that children trace to learn writing and drawing were already used in the 19th century. Numbering the dots turned the exercise into a puzzle: the picture only shows when the dots are joined in the right order.
Puzzle books
In the 20th century such puzzles became a fixed part of children's magazines and puzzle books, in many languages and under many names. They help with counting and with a steady hand. Later came books for adults with hundreds of dots, where the picture stays hidden until the end.
This version
All pictures here are simple drawings of our own: a house, a fish, a rocket, a lighthouse and more. No picture is copied from a book.