I don't understand this as the image being transformed, "space" and "dimensions" seem to originate not with the visual features of the images but with the attributes that the CelebA image set is annotated with. The coverage of the set is not uniform with respect to gender and skin color, I'm not 100% sure how to interpret the attribute values but a some quick math shows that images with "Pale_Skin" outnumber their opposites by about 20 to 1.