Cropping native texture

When a texture is imported, it is kept under the max texture size. If I perform a crop and overwrite the original, I will end up overwriting the original file with a texture that is smaller than the max texture size. Instead, I am hopping to crop the native image and then re-import it with max texture size applied on the cropped image.

For example: If I have an image file of 3000x4000 and the max texture size of the importer is 2048, when I import it, it becomes1536x2048. If I decide to crop 5% off of each side of the image around the border, I will end up having an image of size 1382x1843. Instead, I would like to crop the 5% off of the 3000x4000 image directly, ending up with 2700*3600, and then apply the max texture size. The resulting image should still be 1536x2048.

Is there a way to do so?