how do i create images like picrel?
this sort of monochrome i think i know how to make, just save the png with very little pixel information so there are only like 4 colors
but what about the Xs and dots like its a stitching pattern? i see pics like this sometimes, always with a low resources aesthetic, so i wonder if its some png hack, or if they are artificially added

Ith calledth color dithering, but can be used on 1-bith imathes.
There are several dithering algorithms and you shoudth look abouth ith on deh weth.
The morth youth knoeth the moarth yourth gaeth...

P15979
thanks
i see this sort of image is created using ordered-dithering, but im not sure about the matrix size, i think its 4x4
on imagemagick you just pass `-ordered-dither 4x4` and the `-colors` option is supposed to set the number of colors on the image, but for some reason `-colors 4` only uses 3 colors and `-colors 5` uses 4
but 2 uses 2 color, and 3 also uses 2 colors
6,7,8 use 4 colors
im not really sure how this works tbh, im guessing it controls the color depth not the literal number of colors
also its funny how grayscale images are larger than colored ones, must be some quirk from the way PNG compresses images

oh yea and its really impressive how dithering creates the illusion of a large color depth with very few colors, thats p wack
and i imagine PNG allows hardsetting which color values mean what
bc the 4-color image has white, red and black
and the 5-color image has white, red, yellow and black

oh and the result changes depending on whether -color or -ordered-dither is used first

P15959
dithering easy in GIMP

P16005
P16009
P16010
can you people post guide or how to in gimp?

P16031
Image > Mode > Indexed
or
Colors > Dither
depending on what you want.

another quirk of dithering is that jpeg fucking sucks to compress it, which is not a big surprise considering how it works
the dithered image can even be bigger than the original
P16033
should have let him dick around with gimp for at least 5 seconds before giving away the answer
dont encourage newfaggotry

P16033
I see random dither is one of the options. "Random" dither would be an easy way to hide lots of data in an image, and if you used an encryption method practically indistinguishable from random noise, it would be very hard for distinguishing "random" dither from truly random dither.

Challenge: Find a good way to encode data in "random" dither in such a way that you can extract the data given the encryption key. Should be easy if you assume the original image is available to compare to, more difficult if you don't necessarily have the original image.

P16172
Problem is random dither looks so ugly it's unlikely many people would use it. The deterministic ways of doing dithering look much nicer. There's also a "blue noise" option that looks okay, well, better than the random one at least.

P16212
Forgot to keep filenames; those are random, Floyd-Steinberg, Bayer, and blue noise. I also notice the deterministic ones can produce a lot of aliasing if the image is scaled.