It landed under a leaf near the ground, and I ran to snap pictures. I got a few, but it was so low I couldn't get good ones, so I stuck my finger in front of it until it crawled up. Usually sulphur butterflies fly away when I get close.
It was obviously hurt, so I let it hang from my finger while I took more pictures. I couldn't resist going for an open wing picture, so I bugged it until it opened them. It let me get several photos before it closed them again.
I eventually (ran out of space on my camera) coaxed it off my finger onto the wall in a sheltered corner. A few hours later it was gone.