I went around looking at life-sized sculptures of the Eggs, on Google.
They said they were 3 feet in size.
The Alien3-egg
appears to be 1/2 the size of a normal egg.
The background in Alien3 appears to be some kind of a corridor, or strikingly familiar to the shelves where the Marines kept their Pulse Rifles.
Have a look:
Aliens
AlienĀ³ Though, I admit they don't look that familiar; it's because David Fincher loved slapping the previous directors and films in the face. He even changed the 'USS SULACO' on the ship from black to shiny gold.
That place is really too small for a 3ft Alien egg to fit.
So I say it's small.
Plus, a 3ft egg with resin/stuff inside, with it's weight and the weight of a facehugger, might not be able to stick to the corner of the wall, like that, unless it's small or the resin-base that the Queen applied is made of super adhesive contents.