I had to step away and just getting back, and I like your question. I would like to try to answer in what I think may have happened.
All JMO
I think those sex photos that were found on his camera were mostly from JA putting them on his camera and were hers that she brought with her from previous dates + times. The main reason I think this is the 1 single photo where she has braids and is naked.
Im not good at guessing ages but she sure looked really young in that photo. I think that one may even predate her even knowing Travis. I think she just liked the photo herself and always kept that one.
My theory about the pics is I think JA wanted to make sure his phone had lots of sex photos of the both of them on it. So I think she had brought along a camera memory card that had photos on it OR a flash drive with those pics.
Someone had mentioned Skybot date matching one of the pics dates. So maybe she used a flash drive first to put them on his PC, and then copied them to his camera card via the PC. And by chance the Skybot software updated the date/time or something along those lines.
I think her intent was to NOT have any of the date/times of those sex photos be that particular day. I think she just messed up as she tried to manipulate the date/time stamps on those pics. In fact, I think the detective said most were just thumbnails so maybe as she deleted the pics, the thumbnails never get deleted and are somewhere else on the disc or something along those lines.
But the main thing is the date/time stamps looked "Funny" on some of those pics. Some of them had different "Fonts", so it looked like she had either manipulated them herself or something like Skybot software overrode the date/time.
I think she finally gave up with that idea and just deleted them all, but of course the camera's memory card had certain "trash images" left in the space on the card that was freed up to be written over. Similar to how a PC works where it doesnt actually delete the data but just flags the space as resusable. Which is how she got burned.
Because your original question is right that she did not want the date of the photos to be that day. I think she was trying to make them all be a certain date from a month or so back.
But anyway, Im kind of in a fog on all of it anyway so I could be way off base.
The only thing that I keep thinking for sure is that the 1 sex photo at least was not from that day, and those date/times sure looked funny on some of them. So she was trying to do something. And failed like she usually does.