Avatool Switch

A homebrew that makes changing avatars to custom ones easier. It works by terminating the account service on your Switch which will lead to a crash.

Note that it does write to system save data, which some might consider risky. Also, guaranteed ban online. Use at your own risk.

User guide

Avatars are 256x256 JPG files. Place them in the folder sdmc:/avatar/. Avatool will only see files with the extension .jpg.

Once on the main selection screen:

If the write was successful, you will see the target image change. Reboot and it should show on the home menu and profile screens.

Notes on converting images:

A small guide on using online converter.
Unticking both "progressive" and "generate thumbnail" if you use Gimp (read more).

Works on FW 13.1.0 (Atmosphere 1.2.2) as well as FW 11.0.0 (SXOS 3.1.0).

If you are on FW 16.0.0 you can try this version.

v2.1.0

Now uses a variation of JKSV's newest menu code to prevent crashes from trying to read out of bounds.
Now prevents users from continuing to shutdown the account service without avatars in their sdmc:/avatars/
Further code revisions

v2.0.0

A major portion of the app has been rewritten and runs on the latest Switch firmware
Uses JKSV's newest graphics file/SDL instead of writing directly to the framebuffer
NOTE: It appears my old menu code can be buggy. This will be replaced in the future once JKSV's rewrite is completed. I will also keep an eye out for issues and bugs since I have some extra time for now.

v1.0.2

v1

This tool relies on shutting down the account service. This will eventually make your Switch crash. If you continue:
Avatars are 256x256 jpg's. Place them in the folder sdmc:/avatar.
L and R change the targeted avatar to overwrite.
A overwrites. The target will change if this is successful.