view many photos at once?

hi...
im not sure if this is the right place to post this but ill try anyways. any admins, please let me know if im wrong for this! lol

okay so ive been on this site for a bit and i love it, u guys are all eternity geniuses! hope you can help me with this. the other day, i took a picture and i went to review it by pressing the black button. as i was doing this, i dont know what i did but all of a sudden, my phone review went into this mode whereby i coudl see more than one photo at a time!

I dont know how it happend or how to describe it, but it was like a long line of my photo (think of a timeline) and each photo was overlapping the next either above it or below it (think of a "vvvvvvv" thing with each 'point' being a photo) okay anyways i hope that helps.

my question is... how on earth do i do that again???!!! that was the coolest thing id ever seen!!!!!! if anyone knows, please let me know. thanks

bluejade16

oh!!!...
omg thank you, i thought i had exhausted every button!!!

thank you ))