It's outdoors and it's daytime and the sun is shining. You use Major Image to create an image of a house or other building. The building is windowless. You don't create the illusion of any light sources in the interior, so it's dark inside. Assume someone enters the illusory building but fails their Will save.
1) Once the door is closed, will the person in the building experience darkness as a condition -- i.e., they can't see unless they have darkvision? If they do have darkvision, does it activate, allowing them to see the interior of the building?
2) Okay, let's say you have a creature that's dazzled in sunlight, like an orc or a drow. They fail their save. Are they dazzled inside the "dark" building, or are they okay?
3) Okay, let's say you have a vampire. The vampire enters your illusory building, failing its Will save. Is it burned by the sun, or not?
1. If it were a wall, I'd say a failed save means they can not see past it. If the room is pitch black then I'd say they can not see unless they normally see in darkness.
2. Unfortunately for the light sensitive creature, they are still dazzled despite thinking that they might not be. The area of light they are in is actually bright.
3. The vampire thinking it will be safe inside your building will be surprised to learn that even though it is inside it still burns like it were outside.