Eric,
I will look at the framing again but, in this image especially, the framing inparts a portion of the composition that I want to convey. The framing represents what I was seeing when I clicked the shutter. Framing is an intrical part of the 'whole'.
I think Eric was referring to the large gray "matboard" not to cropping of the 4x5. But perhaps you were also referring to the gray matboard.
Anyway, I find the light rock in the lower left distracting. Some corner burning down there, and a light touch on most of the edges might allow my eye to more effectively work within the square of the image and be even more visually interesting.
The framing is part of the virtual presentation that attempts to duplicate the literal one. That said, however, the 600 pixel height and 471 pixel width does minimize the image. For the web, making the vertical mat smaller would allow an increase in the size of the image which might also increase the width. You've imitated the proportions of a square picture in a 16x20 frame. For the web, a virtual 16x17 or 16x16 would work well and enlarge the photograph.
Your right John. I was scanning a square image from an 8x10 print and trying to mat it as an 11X14 framed piece. I look at it here and it does look out of whack. I think this is what Eric was saying.