Interpret gbr/gih brush with application=imagestamp to load with color.
Otherwise, the brush image returns a grayscale image, which is useful for using the brush in the engines, but not for loading it as a document. BUG:442316
Loading
Otherwise, the brush image returns a grayscale image, which is useful for using the brush in the engines, but not for loading it as a document. BUG:442316
mentioned in commit da4a70a7