Incompatible with VRM Addon for Blender version 2.16.0+

[Mysteryem]

As of Version 2.16.0 of the VRM Addon for Blender, VRM 0.x materials are now imported as VRM 1.0 materials (https://github.com/saturday06/VRM-Addon-for-Blender/releases/tag/2_16_0), which makes them incompatible with Material Combiner (both the current release and the dev-build (technically you can manually set which image is used when using the dev-build, but it's a pain to do that for every material)).

For users, I would recommend downgrading to version 2.15.26 of VRM Addon for Blender (https://github.com/saturday06/VRM-Addon-for-Blender/releases/download/2_15_26/VRM_Addon_for_Blender-2_15_26.zip) of the VRM addon if you want to use Material Combiner with VRM models (and if using VRoid, make sure to export as VRM 0.x and not VRM 1.0).
If you're not using the dev-build of Material Combiner you will still need to either tick "Extract textures images into the folder" when importing your .vrm or unpack the textures yourself after importing.

[Mysteryem]

When using the dev-build (https://github.com/Grim-es/material-combiner-addon/archive/refs/heads/dev-build.zip), the image to use can be manually set from the Shader Editor, but you'll have to do this for every material: