In the shader editor you can specify the colour space of your image texture. In particular, when creating height maps you can specify that the b&w image you’re using to determine the height is 'non-colour'.
In geometry nodes, there isn’t that option - i.e. there's no way of specifying an image as non-colour or RAW.
I'm using a 16-bit greyscale tiff as the heightmap/image texture in geometry nodes, and would be grateful for any advice as to whether that will alter the accuracy of the resulting height maps. And if so, if there's any way around this.