An all-in-one screenshot manager for the 3DS. Browse everything in a grid, preview 3DS captures in real stereoscopic 3D, manage DS screenshots straight out of nds-bootstrap's tar, filter by type or date, and copy or delete individually or in batches.

Named after the Comet Observatory from Super Mario Galaxy, keeping with the Luma/Rosalina naming theme.

• Grid browsing: a real 4×4 grid of thumbnails, not a list, with both D-Pad and touch navigation
• Live stereo 3D preview: the top screen shows whatever's highlighted, in real glasses-free 3D for 3D-capable screenshots
• Copy to the 3DS Camera album: writes proper .MPO files for 3D pairs (with the MPF/EXIF tags the Camera app actually checks for) and plain .JPG for 2D screenshots, individually or in batch
• Delete, individually or in batch, always with a confirmation step
• Filter by All / 3D Only / 2D Only, or drill into a specific Year → Month → Day
• Peek at Luma's bottom-screen capture alongside any screenshot
• DS mode: press L+R to switch to browsing DS screenshots taken with nds-bootstrap/TWiLightMenu++. Reads screenshots.tar directly, with separate tabs for what's still in the tar and what's already extracted to SD — view, filter, copy, and delete from either, with safe extraction (individually or all at once) and widescreen support for games with a 16:10 patch. Also works with Nexus3DS, a Luma3DS fork with its own screenshot naming and an optional date-folder layout. See CHANGELOG.md for the details.
• Merge Top/Bottom Screens, from any 3DS screenshot's More screen — combines both screens into one image and adds it to your gallery with its own badge. No stereo 3D.
• A visual style modeled on the Switch's Album app, right down to sound effects for key actions

Grab the latest release from the Releases page:

• Comet.cia → installs to your HOME Menu with its own icon and banner. Needs a CFW with patched signature checks (Luma3DS, which you already have if you're using Rosalina screenshots) and an installer like FBI. Can also be installed via QR code through FBI's Remote Install feature.
• Comet.3dsx → copy to sdmc:/3ds/Comet/Comet.3dsx and launch from the Homebrew Launcher. No install needed.

See BUILDING.md for full toolchain setup and build instructions (both .3dsx and .cia).

• Made with Claude by Anthropic
• Built with devkitPro/libctru/citro2d/citro3d
• Body font: Poppins by Indian Type Foundry (SIL Open Font License)
• JPEG encoding via stb_image_write by Sean Barrett
• The Morton/Z-order GPU texture swizzle is sourced from the Citra emulator's own code, since it has to be byte-exact to render real games correctly

See TECHNICAL.md for the deeper build notes. The MPO format internals, the background-threaded texture pipeline, and a handful of hardware quirks that took real effort to track down.

If your exported screenshots don't appear in the 3DS Camera app, that's because the management file isn't automatically refreshing when files are added directly to the SD card.

How to fix:

• Open the Camera app → Settings.
• Choose Data Management → SD Card to System.
• You can safely ignore the warning saying "Videos saved on an SD Card cannot be copied to the System Memory." Press OK.
• On the next warning, "Some photos may not be copied. Is this OK?" press No.
• If you see "The management file will now be updated. This may take some time," it worked! You can exit Settings now.
• If not, try again.

MIT — see LICENSE. Poppins and stb_image_write.h carry their own separate licenses; see the note in TECHNICAL.md for specifics.