The only sizes I've ever seen onboard (the Dream) are the 24 oz and 16 oz sizes. The size of the 2015 mug I saw was the 24oz size.
I HIGHLY recommend buying a
handle ahead of time from tervis or bedbathandbeyond, etc, if you are planning to buy one. (they don't sell handles onboard)
Tervis is susceptible to *permanent* hazing/staining from sunscreen. While they will replace a mug that has been marked by sunscreen, that doesn't help when you have a limited edition mug like one gets on DCL.
If you have the handle, you don't have to worry about holding it with a hand that has just applied sunscreen. (like I did. and ruined my 2013 mug that a dis'er had so kindly purchased and sent on to me when I had non-buyer's regret)
Alas, I find no pictures yet, and I didn't get the opportunity to take a picture. They were all gone when I went to do that!