So she sent the picture of “KISS JASPER TOO LONG” to change the FUTURE, not the past. That explains why she made the picture of the text at 8 a.m. and right at 8 p.m. she received a picture of her kissing Jasper. So she controlled the tomorrow’s day, not the past day

Thank you very much for this explanation and detailed replies, it made me realize that even if I think I understand the movie, I actually know nothing 🙂

Now to my question: Out of all the photos Callie had, why did she change to the charade one? What did she want to achieve now that Finn is already fond of her?

This is 100% correct. Well said.

These are some interesting points but I think you misinterpreted a few things. Here’s the timeline as I saw it in the movie.

I think the confusion lies with the time that is represented by the photo that Mr Bezzerides’s got at the beginning of the movie that he thought depicted his death (i.e. the photo with the blood splatter, the coil painting, and his hat WITHOUT THE POLICE TAPE). When Dr. Heidecker is introduced and shows the audience this photo she tells Finn and Jasper that it’s from the next day. As the audience, we are bound by the 2 photo a day narrative (i.e. 8am and 8pm) that we get from the characters and assume that this photo represents the 8pm photo from the next day. However, Mr Bezzerides figured out how to modify the machine to take a photo AT ANY TIME in the future (not being confined to the 8am/pm construct). Thus, this photo represents some time between the 8am photo that Cassie sent back to herself saying to SWAP PHOTO TO CHARADE NIGHT & KILL JASPER TO SAVE FINN and the photo from the previous night that predicted the same scene (i.e. the photo with the blood splatter, the coil painting) only WITH THE POLICE TAPE this time. This fits with the narrative of the movie because after she sends the 8am photo back to herself the previous day she kills Finn (creating the blood splatter on the Dr.’s photo). Also, Cassies note to NOT GET CAUGHT BY THE WINDOW is missing from the photo that represented that days 8pm events (i.e. the one she switched out with the charade night sex photo the previous night). This fits with the end of the movie where it fell off as she was being escorted away by Big Joe. Thus, that night’s scene would be what was predicted in the previous nights photo.

As for the last photo at the end of the movie that we don’t see developed, well this is irrelevant to the plot that involves the characters in the movie. The story revolves around the audience (and the characters) seeing into the future to predict the events that come between then and the present. However, the story that we are introduced to has come full circle and I think it’s meant to represent a return of the audience to uncertainty about what the future has to offer.

Hope this helps!

1) Jasper kills Finn just before 8am Wed.
2) Callie sends a message to her past self at 8am Wed to save Finn by killing Jasper.
3) Past is changed. Now Callie receives the message at 8am Tuesday. But at this point she has no knowledge of exactly what happened on Wed. She can only guess.
4) Callie heeds the message and kills Jasper to save Finn just before 8am Wed.
5) Callie sends a message to herself at 8am Wed to save Finn by killing Jasper because if she doesn’t, the timeline switches back to the original one where Finn dies. She believes that the photo is an instruction from her future self and now she has to make sure the instruction is sent to her past self.

Whenever a message is posted, the PAST is changed. Meaning when the photo is received, it is already PAST version 2. When the photo was taken (message posted), it is FUTURE version 1. Meaning FUTURE version 1 takes place chronologically (if you view the events from outside both timelines) before PAST version 2. It makes no sense that a photo is developed in the absence of agency. Someone has to take the picture in the first place.

The exact same photos have to be taken TWICE in order to finalize an event (no more changes can be made). This cements the past. Otherwise, the past can be infinitely reset/changed.

Now let’s imagine that the past cannot be changed.

Future version 1 (where no photo and hence no message is received):

1) Callie joins Finn at the car.
2) Callie sends a message to past Callie to do the thing she has already done without any instruction from her future self.

How does that make any sense?

I feel that this makes more sense (and avoids the usual time travel paradox):

Future version 1 (where no photo and hence no message is received):

1) Callie doesn’t join Finn at the car.
2) Callie regrets her decision and sends a message to past Callie to join Finn at the car.

Past resets. Past version 2:

3) Callie receives message.
4) Callie joins Finn at the car.
5) Callie sends a message to past Callie to join Finn at the car to finalize the event.

The idea would be that she is doing all this to help another version of herself from an alternate time line. She still gets screwed but that other version of herself in the past is better off…. one could compare it in the real world with how people have the instinct to sacrifice themselves for their children for example. They know they will die but their kids will go on… that’s the only way I can make any sense of it.