Looks to me like Jimmy's finger is holding down the camera shutter button - perhaps the photos are in the correct order and show the Joker walking away after the apparent shooting.
As he was walking away, Great Rao abruptly turned on his heels. "Oh!" he exclaimed. "Yeah, I have one last question, Mister Poimanus." He dug into the pocket of his grubby raincoat and withdrew a scrap of paper bearing some notes in pencil. "It's something that's been bothering me, see? If the guy's taking pictures of the guy who, forgive me, shot him, shouldn't the last one be on top? I mean, the one where you see the blast, uh, the crime in progress?"
Sweat beaded on Permanus' forehead. "Yes, I see what you mean, Detective. Perhaps the perpetrator returned to the scene of the crime and rearranged the photographs?" He eyed his interrogator uneasily.
Rao scratched his forehead. "See, I thought of that, too... But why would a guy do that, you know what I mean? Then I remembered Missus Rao, she's going on this course, see? All of a sudden, she gets it into her head she wants to be a pathologist. Don't ask. So she tells me all about - what's it called? - Igor Morris or something. It's like how the body gets all stiff when it's, you know, I'm sorry to bring this up..."
"Dead, you mean?"
"Well, yes, sir, that's what I meant, sir. So say the fingers go all stiff - I hate to mention this, sir, I know it's a difficult time - and press on the button, and the pictures are actually taken after Mr. Olsen was, bless his soul, shot?"
Permanus relaxed. "Doesn't rigor mortis take some time to set in?"