REGRESSION placeholder border left behind after image finishes loading

• Component: Layout and Rendering
• Status: VERIFIED FIXED

If the final layout is finished and an image hasn't finished loading yet, a grey box saves as a placeholder. 
The border extends beyond the image's area, and when the image is finally loaded, the part of the border 
that's outside the image just stays there.

To reproduce you need an image that takes long to load (and that isn't already on your cache). You can go 
to http://g4.mitzpettel.com/seeTheBorder2.html (until I take it down).

Expected: grey placeholder frame to go away once the image is fully loaded
Actual: gray frame remains. If the page is reloaded (from cache), the frame disappears

I'm almost certain that this regression started with the patch for bug 4924

Created attachment 3893 [details]
expected rendering

Created attachment 3894 [details]
actual rendering

[Darin Adler]

Got this fixed.