Resolution in itself has no sense.

It is always related to a medium of reproduction being it paper or the PC screen.

What is used for textures is size in pixels, not resolution.

In 3d games most of the textures have predetermined sizes (usually powers of 2) because so they can be loaded into graphic cards memories very fast. Some progamsd allow the modders to change the size till it stays a power fo 2, others can't, and anyway you'd have to reskin the model because the textures will not be referenced correctly anymore during the 3d rendering.

This last operation cannot be done yet till a converter is lacking, because for doing it you need to import the model into a 3d program, retexturing it, and then exporting it back in a format MTW2 can use.