I've gotten the digital pictures only. It's the best approach when you only want a few and are not sure which ones to do get and need to rush thru it. Instead you do it at home.
For the 10/15/20 pictures options, you still get the CD with ALL the prints, however you will only be able to unlock the full resolution versions based on what you purchased. I believe you can purchase additional ones by contacting them. I've had problems with the CD on our second cruise, and they actually gave me some additional prints for my troubles (support was VERY GOOD).
However, note that the borders ARE on all of the pictures. Note that on our first cruise, we purchased the length of cruise CD. On this one, some pictures were missing the borders (this was in August 2012). Not the case on the last two cruises where all the pictures had their own borders.
One more thing. Regarding print size, the pictures are already sized accordingly with their respective borders as originally printed - 8x10 (1.25 ratio) or 6x8 (1.33 ratio). This is an issue as you cannot easily crop a picture if you change the size. A 5x7 (1.4 ratio) or a 4x6 (1.5 ratio) are other typical sizes to print and because of the borders, it's very hard to change.
Formal pictures will have just a logo and no borders so these are the easiest to crop. But character pictures have intricate borders and makes it hard. And those 6x8 pictures, forget about getting a frame for it. To print these, I've simple expanded them to 8x10 (adding a white 1" border all around) and then trimmed them (they are in albums) or got a matt to use on an 8x10 frame.