This sounds like it might show something, but I'm not sure. Probably makes sense to start with some pics that don't have messages in them. Get an idea of what a normal jpg, png, etc, looks like. Each format is different and most of it should just be "random" where the bits of the picture are.
Then add a message to each pic and compare the original against the one with a message?
Steg. messages are supposedly hidden in the bits of the image, by changing them slightly across the actual image. 251,143,207 becomes 251,143,208 maybe, RGB values I mean. I say "supposedly" because I'm not an expert at all.
I don't think you're going to find a large area of a single color indicating a message. Someone posted recently that images with messages were larger than the originals. So maybe there are apps that just append the message somehow? Seems like that would definitely show up in binvis.
I'll try adding messages to a few test files with pixelknot, and post the binvis comparisons. Apparently that's not the code being used, though. It adds a header to the pics, which I didn't see on the SF pics.
Yes, on android. Open the app and pick a picture, then add the message and password. It finishes with "send the pic" and lets you choose Drive or mail or whatever. I mailed the pic to myself. It doesn't change the pic that you add the message to, on the tablet.
Then, get the pic out of mail, put it back on the tablet with a usb cable or wifi file transfer or whatever. Use a file manager to get to the pic, and when you hit it, the "open with" list will include pixelknot. Hit that, and it gives you the screen to enter the password and recover the message. Takes about a minute, for correct or wrong passwords.
The large hi res space force picture just hangs, when I try that. Might be too large for the app. The small one finishes with an error immediately, not sure if it supports webp format. But like I said, I don't think that pixelknot is the app they used. Even though Q mentions it specifically.
I tried a few different things, took a picture with the camera from the app, and a random one I downloaded. Didn't try the recent pic where he's walking into the building with the row of stars across the pavement. But again, the space force pics do not look like they came from pixelknot. It leaves a header in the pic that shows up as text, and those pics don't have that.
Test results here with three different files, comparing the original, a short message, and a longer message, with binvis. Original files are all jpgs, same version as the space force one, "JPEG image data, JFIF standard 1.01". Binvis output files are all png. I checked that catbox.moe doesn't change the file at all, so the test messages should be recoverable with pixelknot. Password for all the files is WW1WGA, the longer message is the shorter one plus a bit more text.
Links here are original, original with short, original with long, then binvis of original, binvis of original with short, binvis of original with long. The only useful part maybe is what the original jpgs look like in binvis? Files with messages are a lot smaller than originals, pixelknot is doing some kind of compression?
This sounds like it might show something, but I'm not sure. Probably makes sense to start with some pics that don't have messages in them. Get an idea of what a normal jpg, png, etc, looks like. Each format is different and most of it should just be "random" where the bits of the picture are.
Then add a message to each pic and compare the original against the one with a message?
Steg. messages are supposedly hidden in the bits of the image, by changing them slightly across the actual image. 251,143,207 becomes 251,143,208 maybe, RGB values I mean. I say "supposedly" because I'm not an expert at all.
I don't think you're going to find a large area of a single color indicating a message. Someone posted recently that images with messages were larger than the originals. So maybe there are apps that just append the message somehow? Seems like that would definitely show up in binvis.
I'll try adding messages to a few test files with pixelknot, and post the binvis comparisons. Apparently that's not the code being used, though. It adds a header to the pics, which I didn't see on the SF pics.
Yes, on android. Open the app and pick a picture, then add the message and password. It finishes with "send the pic" and lets you choose Drive or mail or whatever. I mailed the pic to myself. It doesn't change the pic that you add the message to, on the tablet.
Then, get the pic out of mail, put it back on the tablet with a usb cable or wifi file transfer or whatever. Use a file manager to get to the pic, and when you hit it, the "open with" list will include pixelknot. Hit that, and it gives you the screen to enter the password and recover the message. Takes about a minute, for correct or wrong passwords.
The large hi res space force picture just hangs, when I try that. Might be too large for the app. The small one finishes with an error immediately, not sure if it supports webp format. But like I said, I don't think that pixelknot is the app they used. Even though Q mentions it specifically.
I tried a few different things, took a picture with the camera from the app, and a random one I downloaded. Didn't try the recent pic where he's walking into the building with the row of stars across the pavement. But again, the space force pics do not look like they came from pixelknot. It leaves a header in the pic that shows up as text, and those pics don't have that.
Test results here with three different files, comparing the original, a short message, and a longer message, with binvis. Original files are all jpgs, same version as the space force one, "JPEG image data, JFIF standard 1.01". Binvis output files are all png. I checked that catbox.moe doesn't change the file at all, so the test messages should be recoverable with pixelknot. Password for all the files is WW1WGA, the longer message is the shorter one plus a bit more text.
Links here are original, original with short, original with long, then binvis of original, binvis of original with short, binvis of original with long. The only useful part maybe is what the original jpgs look like in binvis? Files with messages are a lot smaller than originals, pixelknot is doing some kind of compression?
eggs,
https://files.catbox.moe/ktcmyb.jpg
https://files.catbox.moe/xj675r.jpg
https://files.catbox.moe/vjrfd0.jpg
.
https://files.catbox.moe/gr4b18.png
https://files.catbox.moe/ffccov.png
https://files.catbox.moe/1hf61v.png
middle east,
https://files.catbox.moe/ez9z2k.jpg
https://files.catbox.moe/0vy69q.jpg
https://files.catbox.moe/nxjyyp.jpg
.
https://files.catbox.moe/lcoxo0.png
https://files.catbox.moe/dfxyut.png
https://files.catbox.moe/69bh25.png
harbor,
https://files.catbox.moe/tu8zyv.jpg
https://files.catbox.moe/a123sk.jpg
https://files.catbox.moe/qt6d3t.jpg
.
https://files.catbox.moe/asoys0.png
https://files.catbox.moe/9micd9.png
https://files.catbox.moe/lmbxqw.png