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How do these photos work? Can they be made with photoshop?
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>>428261
do you have more examples?
>>
This is just a test
>>
File: test2.png (1.4 MB, 739x1024)
1.4 MB
1.4 MB PNG
>>428290
test 2
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I found this
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>>428261
i have no idea how this is done

but i am guessing that the creator of this image knows exactly how 4chan resizes for thumbnails and makes it so the minimum number of pixels are for the other picture. when you blow it up, you get all the pixels and the thumbnail pic is distributed among them in small quantities and you barely notice it at all, certainly no coherent picture
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File: 1242114112414.png (1.08 MB, 1144x830)
1.08 MB
1.08 MB PNG
>>428261
I mean look very closely and the entire picture is made up of these circles in squares.

What if each of those squares turns into one pixel in the original thumbnail so the trick is to average each of those squares by cutting out a bit in each until the 'average' is the pixel you do want.

once you know how it translates you can write a program to do it all for you.

i don't know anything so what's the code 4chan uses to resize these images? how does the javascript work?
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File: 2341251235235.png (22 KB, 1041x86)
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22 KB PNG
>>428261
so if you look at the code on this page, it doesn't do anything with javascript. your computer isn't doing a thing. it actually has two separate files... one of the files is the thumbnail, and the other is the larger one. you click and it changes which image it shows you. That's it.

Which means when you upload a picture, there's some code running on 4chan servers that takes that image, shrinks it into an appropriate sized thumbnail, and then displays it.

Whatever program they are using, obviously someone has figured out a way to get it to encode a completely different image as the thumbnail.

This also means that the original file that exploits the 4chan thumbnail maker program, is destroyed once this gets posted. it splits into thumbnail, and non thumbnail, and you never get to see the original file to inspect how it does it.

the real question is how does 4chan convert an image to a thumbnail? is it using some popular software? did they write their own in C or something? it would have to be pretty damn fast and bare bones to handle 4chan or they'd waste so much resources.

you'd have to now understand some low level stuff about how an image could be translated into a thumbnail. like what EXACTLY happens.
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>>428300
This isn't really about how 4chan creates thumbnails. Both the image of the girl and kojima exist in the same image, using a color dithering trick.

Now, normally when viewing this image, you'll see both images layered on top of eachother (although it's easier to see the girl than it is to see kojima), but for some reason, when seeing the image on a web browser, you'll only see kojima.

I'm assuming this exploits something about the way browsers render images, but I haven't quite figured it out yet.
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>>428314
I think it has to do with alpha channels
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File: 1630230476277.png (404 KB, 762x415)
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testing with OC
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>>428371
Fucking how
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>>428373
obviously didn't get it completely right
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File: 1647747767926.png (204 KB, 306x306)
204 KB
204 KB PNG
will it work better with square images
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>>428376
try it with the resolution of the original image
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>>428261
yes
just google
its prolly stupidly easy
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>>428400
Google search results are trash now.
>>
/g/tard here, there was a thread awhile back where some scripts were shared, I saved 2 to play around with.
Here is the first
# Title -- Fake Thumbnails
# Purpose -- Take 2 image files (png) as input and output 1 image file, this file will have the contents of the first argument and
the thumbnail of the second argument
# Explaination -- The website 4chan is an imageboard, you can post images along with text, these images are shown next to the text
in a thumbnail, when you click on the thumbnail the full image is loaded.
# usage -- ./fakeThumbs WantedImage.png WantedThumbnail.png outputName.png

[ -z "$1" -o -z "$2" ] && echo "Need 2 input images." && exit 1
[ -z "$3" ] && out="out.png" || out="$3"

ffmpeg \
-loglevel 'error' \
-y \
-i "$1" \
-i "$2" \
-filter_complex \
"`echo \
'color=c=black[mask];' \
'[mask][0:v]scale2ref[mask][main];' \
'[1:v][main]scale2ref[scnd][main];' \
'[mask]drawgrid=w=2:h=2:c=white,format=rgb24[mask];' \
'[main]colorlevels=romin=0.01:gomin=0.01:bomin=0.01' \
':romax=0.21:gomax=0.21:bomax=0.21,eq=gamma=10.0,eq=gamma=1.4' \
',format=rgb24,split[main][temp];' \
'[scnd]colorlevels=romin=0.0:gomin=0.0:bomin=0.0' \
':romax=0.8:gomax=0.8:bomax=0.8,eq=gamma=0.7,format=rgb24[scnd];' \
'[temp][scnd]blend=all_expr='"'B - 0.33*A + 84'"',format=rgb24[scnd];' \
'[main][scnd][mask]maskedmerge[vout]'`" \
-frames:v 1 \
-c:v png \
-f image2 \
-map '[vout]' \
- | \
convert \
- \
-set 'gamma' '0.027' \
-define 'png:include-chunk=none,gAMA' \
"$out"
>>
And the second
# Author -- Anonymous 01/27/22(Thu)18:07:23 No.85420758
# Title -- Fake Thumbnails
# Purpose -- Take 2 image files (png) as input and output 1 image file, this file will have the contents of the first argument and
the thumbnail of the second argument
# Explanation -- The website 4chan is an imageboard, you can post images along with text, these images are shown next to the text
in a thumbnail, when you click on the thumbnail the full image is loaded.
# usage -- ./fakeThumbs WantedImage.png WantedThumbnail.png outputName.png

high="$1" # High image (full-size original view)
low="$2" # Low image (thumbnail) (should be the same size)
output="output.png"
[ ! -z "$3" ] && output="$3" # Output image
size=$(convert "$high" -format "%wx%h" info:)
convert "$high" -alpha off +level 3.5%,100% -gamma 20 high_gamma.png
low_gamma="-alpha off -gamma 0.8 +level 0%,77%"
convert \( "$low" $low_gamma \) high_gamma.png \
-compose Mathematics -define compose:args='0,-0.33,1,0.33' \
-composite low_adjusted.png
convert low_adjusted.png high_gamma.png -size $size pattern:gray25 -composite \
-set gamma 0.022727 -define png:include-chunk=none,gAMA "$output"
rm high_gamma.png low_adjusted.png
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File: fake.png (472 KB, 600x399)
472 KB
472 KB PNG
>>428458
testing this script
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File: fake2.png (558 KB, 600x399)
558 KB
558 KB PNG
>>428459
testing this script
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>>428459
>>429089
this one matches originals better

thx for sharing
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>>429088
cant decide which one i like more
>>
def like the second one you made more, i like the light blue as opposed to the darker blue. The original photo op posted looks really good tho, you do not see the dots in it at all and you are totally caught off guard, the photos produced from anons script very dotted/pixelated
>>
File: 01.png (114 KB, 294x231)
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File: 02.png (2.3 MB, 1482x2048)
2.3 MB
2.3 MB PNG
>>
>>428458
>>428459
This script is only for linux?
>>
File: Legs.gif (267 KB, 460x613)
267 KB
267 KB GIF
They are messing with you.
>>
>>430058
Nope, I changed the extension name to png and it worked in Chrome but when I uploaded it to 4chan it changed the extension.
>>430054
says ffmpeg, Idk, I guess it works with Windows.
Never needed ffmpg, maybe I should introduce myself with it anyway.
>>
>>430059
The second script doesn't have ffmpeg. I made a *.bat file but it returns errors. Why do they post scripts without any detail?





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