Mobilers in case you have noticed....or not, there is a new storage icon on the dragon pics in the dragon book. There has been some confusion as to why only some dragons which you know are in storage are not showing the storage icon. A user in one of the facebook groups and this is the info she came up with regarding who gets the icon and who doesn't.
THE EGG ICON IN DRAGON BOOK. APPEARS IF:
You do not have this dragon on your island .. i.e it has never been hatched: dragon is grey in the book, but you have this dragon's egg in storage. The egg icon will also appear if you have previously sold the dragon, colored dragon and have an egg in storage.
You have put that dragon into the dragonarium, If you have an egg in storage the egg icon will appear. The book treats these dragons as if they are not on your island, ie the same as if they have never been hatched. If you take the dragon out of the dragonarium and place in a habitat, and have an egg in storage.. the egg icon WILL NOT APPEAR.
THE EGG ICON DOES NOT APPEAR:
If you have hatched a dragon.. ie Imp dragon, and it is in a habitat, even if you have an Imp egg in storage.. The egg icon will not appear, unless you either sell it, or put it in the dragonarium
NOTE: Not sure as yet though if the dragon is breeding / on a tower or busy, if the egg icon vanishes when they are unavailable..
(Can't check, as have no eggs in storage for my tower dragons)