These challenges involve processing pre-existing image files, by altering them in some way, gathering statistics, or other image processing tasks.

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23
votes
5answers
1k views

Photomosaics or: How Many Programmers Does it Take to Replace a Light Bulb?

I've compiled a mosaic of 2025 headshots from the avatars of the top Stack Overflow users. (Click the image to view it full-size.) Your task is to write an algorithm that will create an accurate ...
256
votes
34answers
45k views

American Gothic in the palette of Mona Lisa: Rearrange the pixels

You are given two true color images, the Source and the Palette. They do not necessarily have the same dimensions but it is guaranteed that their areas are the same, i.e. they have the same number of ...
12
votes
9answers
851 views

Dither a Grayscale Image

Dither a grayscale image into pure black and white with your own algorithm. Guidelines: You must come up with your own new algorithm. You cannot use pre-existing algorithms (ex. Floyd-Steinburg) but ...
13
votes
3answers
779 views

Miniature Faking

As any amateur photographer can tell you, extreme post-processing is always good. One such technique is called "miniature-faking". The object is to make an image look like a photograph of a ...
21
votes
3answers
969 views

Hiding information in Cats

You are a secret agent trying to communicate with your fatherland. Of course the information needs to be hidden so no one eaves drops your message. What would be better suited than a cat? Everyone ...
25
votes
17answers
3k views

Output an image of your source code (not-quite-a-Quine)

Code golf: Print an image of the source code. Requirements Must output the image of the source code itself, not a version stored elsewhere and retrieved at run time. Code must be legible enough ...
11
votes
4answers
415 views

Recognize ASCII art numbers

Challenge Recognize ASCII art numbers. To make things interesting, three random points in the image might be flipped. For example: ***** * ** ** ** ** ** Input A 7x7 ...
11
votes
3answers
574 views

Freehand red circles

Over on http://meta.stackoverflow.com, we have a few memes of our own. One of them is Freehand Red Circles. See this post: So, the challenge is, can you draw freehand red circles... with code? ...
7
votes
4answers
594 views

Produce the number 2014 from an image

In the 2014 challenge, Michael Stern suggests using OCR to parse to 2014. I'd like to take this challenge in a different direction. Using built-in OCR from the language/standard library of your ...
41
votes
8answers
3k views

Encode Images into Tweets (Extreme Image Compression Edition)

Based on the very successful Twitter image encoding challenge at Stack Overflow. If an image is worth 1000 words, how much of an image can you fit in 114.97 bytes? I challenge you to come up with a ...
4
votes
4answers
336 views

Determine which of two ImageMagick .TXT images is more saturated

You have two images (64x64 pixels each): Your program must take the file names of each of them as command line arguments and determine which has more average saturation among their pixels. The ...