A Challenge Worthy of the Drawing Room

My dear reader,

I have devised a small amusement for you, though I confess, it came about quite naturally. It seems some mischievous hand (I will not name names, but I have my suspicions) has left subtle changes scattered throughout my drawing room. Between these two images, there are four such differences, including one rather handsome blue lattice egg.

I invite you to take up the challenge. Spot all four, and leave your answers in the comments below. To m...