I've heard that the photos don't show up on the
MDE app, if that's where you were thinking about looking at them. Personally, I'd try to check them out at the photopass center in the parks every day. The main reason I say this is because there's always a chance that the band may not scan correctly and a few photos could come up missing. The photopass CMs are always willing to help find missing photos, but it's a lot easier to do the day they were taken, when they can talk to you in person and see you, than trying to do it through email at home.
I'd say if there are photos you "can't live without," definitely make sure they made it into your account before you leave the park.
Side note: I'm definitely not trying to worry you, even though I know it sounds that way. I've used the photopass products many times and have only ever lost a few pictures, all of which the CMs were able to find for me. It's definitely not an issue that happens all the time, it's just something to be aware of, is all. I hope this info helped, and enjoy your trip!
ETA: It usually takes about 2 hours for photos to show up in the photopass system at the parks, and up to 24 hours for them to show up on your personal account.