If you have missing photos, you can call the customer service number for MM, and they can help locate them. Before you call jot down what location, day , and approximate time you are missing the photos from, if you know, and it makes it easier for them to look up. A number of mine were missing from Dec. trip, and I called them and was able to get all of them on my account. If you have only accessed them via the app, pull them up on a desktop. They told me this when I had to call, as sometimes they are not all showing up on the app for some reason.
I'm assuming you have not reached your expiration date. If so, you can edit your photos, add borders, make black and whites, etc. You should save each one as a copy, to also keep your original. When you have all that completed, you will have an option to download all the photos, the original plus the ones you have added in editing. You no longer order a CD, they just download to your computer, and you can put on a flash drive if you want.