The free pack Petixel Characters got  an update :

Technical fixes:
- Now, the charsets containing 8 slots work properly in RPG Maker.

- Charset of seperated Man, Woman and Child of both colors have been added and will be compatible with upcoming customizable characters asset packs.

Visual Changes:
- Characters' chin has been modified so they don't look like they have a beard despite they gender or age.
- Characters' frames facing left and right has been placed a pixel upper
- Female breasts are now visible when facing left and right
- Less shadow in the child' back

Note : Characters from the Prototype asset pack haven't been affected, but this could happen in the future.
In this case, a devlog on the Prototype page will be written.

I left the old version available in case you like it better.
Just know that new characters asset pack are coming and will be made for the new version.
If you want to make them work, just remove $ from the file name, so :
!$CharasNaked_Color.png
!CharasNaked_Color.png

I apologize for not noticing and solving this problem sooner. Enjoy!