Fascinating. It appears to me that a lot of the apparent differences are due to the relative proper motion of our solar system w.r.t. the eagle nebula. This proper motion allows us to see the nebula in 3-D, as our viewpoint has moved enough in 20 years to give us human-viewable parallax.
If you resize the photographs on your monitor (windows photo viewer will do) so that both pictures represent the same solid angle and are the same size, and then position them side-by-side on your monitor, and then go cross-eyed so your left eye is pointing at the RH picture and your right eye at the LH picture, then the 3-d nature of the nebula jumps out at you.
That part at the top, that I call the 'head', the part that is the fox's ear is clearly sticking out toward us, and the part that sticks out at the base of the neck, just above the shoulder, is pointing away from us, its the other arm! There are other 3-D details too, take a look!