I caught this today on my camera (central Spain) and upon studying the underside it seems clear that it is a green-veined white. However, my field guide (Haahtela, Saarinen, et al) states that the forewing upper surface has no or a faint black spot (male) and two spots (female). With only one spot it has to be male but the spots look strong and well-formed to me. Could this be a new sub-species or is the field guide wrong?
The Collins Butterfly Guide says that the species is extremely variable and evolving, and that the experts don't really know what's going on. Your photos are somewhat in between what they describe as Artogeia napi meridionalis in S Europe and the Moroccan form A. n. segonzaci. But who knows what subspecies are just not in guides or what local variability there is within groups. This page has some photos.