7And he brought me to the door of the court; and when I looked, behold a hole in the wall. 8Then said he unto me, Son of man, dig now in the wall: and when I had digged in the wall, behold a door. 9And he said unto me, Go in, and behold the wicked abominations that they do here.
10So I went in and saw; and behold every form of creeping things, and abominable beasts, and all the idols of the house of Israel, portrayed upon the wall round about.
11And there stood before them seventy men of the ancients of the house of Israel, and in the midst of them stood Jaazaniah the son of Shaphan, with every man his censer in his hand; and a thick cloud of incense went up.
12Then said he unto me, Son of man, hast thou seen what the ancients of the house of Israel do in the dark, every man in the chambers of his imagery? for they say, The LORD seeth us not; the LORD hath forsaken the earth.
-- Ezekiel 8:7-12 (KJV)
In verse 10, Ezekiel describes what he saw when he entered through the door, "every form of creeping things, and abominable beasts, and all the idols of the house of Israel, portrayed upon the wall round about.". Then in verse 11,he observes seventy elders who "stood before them", that is, the portrayals1 (carvings) on the wall, with Jaazaniah in the midst of the elders.
In verse 12, the LORD says, rhetorically, "hast thou seen ...", since He knows what Ezekiel has just witnessed for himself.
So, "the chambers of his imagery" is a reference to the room they were currently in, and other rooms within the Sanctuary of the Temple2 that were similarly decorated with carvings. There were many rooms in the Sanctuary, but the number of them is of little consequence. The mention of "seventy" elders, indicates that all of the administrators of service in the Temple were participants in its desecration.
חָקָה (Strong's H2707 - chaqah) - cuttings, carvings, engravings
There were many rooms within the Sanctuary of the Temple,
see Rose Guide to the Temple -