Well the rumor is they will get bigger, just how much Bigger I haven't heard.
Ymir being one of the oldest Asgardian beings I would think he could be enormous compared to the regular Frost Giant.
Here's Ymir in the latest showing from the Free comicbook couple years ago.
Responsibility, Duty, Honor these are not
mere virtues to which we must aspire
they're Essential...to every soldier
....to every King.
Coulson, "If the details of this gets out, the operation would be complimized"