Hacking Would it be possible to edit the games that can have their screenshots sent on Swapdoodle?

Nicky P

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I use swapdoodle a lot and I'd love to send some of my Tomodachi Life screenshots or even screenshots I take with Luma 3ds to my friends via Swapdoodle. Would there be any way to make a rom hack or something for Swapdoodle that allows any screenshot or anything from the camera roll to be sent to someone?
 

Nicky P

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Swapdoodle doesnt read Luma Screenshots though. That's the issue. That's why I asked on here if anyone knows if it would be possible/what tools would be needed to change the readable screenshots to anything on the 3ds's sd card rather than what the restrictions are now
 

Kwyjor

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Yes? If Swapdoodle only recognizes pictures that can be viewed in the 3DS Camera app, then you can change your Luma screenshots (or anything else) into a format that can be viewed by the 3DS Camera app.
 

Nicky P

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Yes? If Swapdoodle only recognizes pictures that can be viewed in the 3DS Camera app, then you can change your Luma screenshots (or anything else) into a format that can be viewed by the 3DS Camera app.
Swapdoodle only recognizes images from specific games, like Pokemon Moon and Animal Crossing New Leaf. It doesn't recognize any other screenshots that aren't taken from the select few games. What I'm asking is if there would be a way to change either
A. The titles that Swapdoodle can read (I.E. Making it so any game or anything on the SD card could be read)
or
B. Changing the images so that they can be recognized by Swapdoodle. (I.E. Changing a Tomodachi Life screenshot so that the 3ds and Swapdoodle recognize it as an Animal Crossing New Leaf screenshot)

The list of images that are currently recognized and usable by Swapdoodle are here
 

Kwyjor

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That is a considerably clearer question.

Those games all have their own custom in-game screenshot function, right? Can you find where those screenshots are stored on your SD card? What happens if you just put your own image (with the same dimensions and color depth) in the appropriate folder?

If Swapdoodle doesn't recognize images added in that fashion, then try opening one of the screenshots that does work in Swapdoodle on your PC in an image editor, and save it under a different name without making any changes. Then compare the new file with the original in a hex editor, and hopefully there will be some indication of whatever subtle trickery is used to distinguish real screenshots from substitutes.
 

HelpTheWretched

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IIRC, some games with a screenshot feature also create a small .bin file with the same filename. I think it's some kind of digital signature, and it's probably how Badge Arcade only allowed you to post screenshots of the Home Menu (yeah, I tried messing with that a few years ago) but I have no way of proving this or figuring out how to spoof them.
 

Nicky P

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IIRC, some games with a screenshot feature also create a small .bin file with the same filename. I think it's some kind of digital signature, and it's probably how Badge Arcade only allowed you to post screenshots of the Home Menu (yeah, I tried messing with that a few years ago) but I have no way of proving this or figuring out how to spoof them.
Where does it save the .bin files? I cant seem to find them in the DCIM folder
 

HelpTheWretched

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Where does it save the .bin files? I cant seem to find them in the DCIM folder
I don't remember, but if they exist then they're probably in the same folder.

My comment was a complete guess and might have nothing to do it, so I'd say try Kwyjor's suggestion.
 

Nicky P

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2021-10-27_19-46-27.606_top.png

GUYS I F*cking did it! I edited an image and was able to get it recognized by Swapdoodle!
The steps to complete this process were
1. Take 2 screenshot of a game that actually works. (I used a generated photo from the 3ds Mii Maker)
2. Put both on your PC and edit one
3. Open both up in a hex editor (Or just find a free one where you can do comparisons) and copy all of the lines from 000086c2 down on the unaltered picture and paste them onto the altered picture.
4. Save the altered image with the new hex lines and put it on your SD card
5. Now it works!

I dont know how I'd be able to turn screenshots from one game into screenshots of another, but this is a start
 
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The Real Jdbye

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View attachment 281995
GUYS I F*cking did it! I edited an image and was able to get it recognized by Swapdoodle!
The steps to complete this process were
1. Take 2 screenshot of a game that actually works. (I used a generated photo from the 3ds Mii Maker)
2. Put both on your PC and edit one
3. Open both up in a hex editor (Or just find a free one where you can do comparisons) and copy all of the lines from 000086c2 down on the unaltered picture and paste them onto the altered picture.
4. Save the altered image with the new hex lines and put it on your SD card
5. Now it works!

I dont know how I'd be able to turn screenshots from one game into screenshots of another, but this is a start
The part before 0x86c2 must be some kind of header, but at least we know there is no checksum in the header. So you may be able to get away with simply copying that part from a working file just like you did and using the same header for every file, so all you'd need to do is figure out what sort of compression method is being used for the image in order to generate a recognizable image from scratch.
 
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Nicky P

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The part before 0x86c2 must be some kind of header, but at least we know there is no checksum in the header. So you may be able to get away with simply copying that part from a working file just like you did and using the same header for every file, so all you'd need to do is figure out what sort of compression method is being used for the image in order to generate a recognizable image from scratch.
I cant seem to figure out how to put bigger images onto the original. I think the issue is that trying to use a bigger image uses more pixels? I don't know. When I try to do the method stated above, the edited image isn't missing any hexadecimal lines. It's gained a bunch. If I try and delete them, it messed up the picture by deleting pixels... So I think you'd have to try this method with two images of the same size or scale the edit you want to make down.
 

The Real Jdbye

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I cant seem to figure out how to put bigger images onto the original. I think the issue is that trying to use a bigger image uses more pixels? I don't know. When I try to do the method stated above, the edited image isn't missing any hexadecimal lines. It's gained a bunch. If I try and delete them, it messed up the picture by deleting pixels... So I think you'd have to try this method with two images of the same size or scale the edit you want to make down.
You mean higher resolution? That makes sense, all screenshots on the 3DS are the same resolution.
 
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