Hey, thanks!!
Some of them are really grainy like the last one, here's the original :
https://www.flickr.com/photos/the_sorrowful_wife/29736141964/in/dateposted-public/
it's this weird slide expired film that creates organic grain, I love it, but it's hard to find it, this photo shop had a box of it, and now they're sold out, and I can't find it anywhere else.
but, yeah. some of them got grain from compression.
I think you can spot that is digital noise.