Nonogram — Turn your picture into a puzzle

Upload a jpg-file. (Other file formats are also allowed — probably.) Choose the options, and push the button.
The image is used to build a Nonogram [Wikipedia; explanation; example puzzle with Alan Turing].
It takes some time ... especially when the file is large (so please do not use images larger than 100 kB;
larger than 500 kB is even forbidden), or if the chosen options happen to be "wrong".

Basic options De jpg-file:

The image that is to be turned into a Nonogram. At most 500 kB.

Height:

The height of the Nonogram; width is scaled accordingly. Constructing bigger Nonograms takes longer.

Use edge detection:

When edge detection is chosen only the contours in the image are used to construct the Nonogram. Constructing puzzles this way usually takes longer.

Smart solver:

When a smart solver is used, more difficult Nonograms can be constructed. This usually takes longer. By the way, a difficulty measure is provided for the puzzles.

Make multiple puzzles Create multiple puzzles from this image:

If you wish to create multiple puzzles of the same image, more options will be made available. It takes much more time.

Initialization Initialization-method: Solvable puzzle Percentage black pixels:

Solvable puzzle: A solvable puzzle is constructed immediately. Quick, but not available when you want multiple puzzles.
Percentage black pixels: The given percentage of pixels in the puzzle is made black. Then, the puzzle is made solvable. Optimal value depends on the image, but something between 30 and 40 usually works well.

Initial threshold:

At lower threshold values it is possible to construct puzzles with fewer black pixels.

Threshold stepsize:

A higher stepsize can speed up Nonogram construction, but may lead to puzzles that don't resemble the input image that much.