Okay, I saw this yesterday after proofreading a number of previous posts and it caused me a whole day of grief. Something is going on with AtD where it is doing needless code reformatting, which ends up eventually stripping image tags completely.
Save a draft with properly formatted tags and it all stays the same when the screen comes back,
Proofread a post (even without changing any found spelling errors) and the first thing that happens is the img tag gets totally re-written. The closing " /" is stripped out before the > and everything is re-ordered, colors in a style specification are, IMO, needlessly being converted to rgb from hex; adding in a whole bunch of extra characters to specify the same color. #eee is rgb(238, 238, 238) but why change it?
margin: 8px 1px 1px 1px;
gets changed to
margin: 8px 1px 1px;
Where's the fourth value?
margin: 8px 0 0 0;
margin: 8px 0pt 0pt;
Fourth value is still missing and I suppose that 0px == 0pt but why change that if that is not the way the user prefers to work?
Saving the draft from there strips out the whole inline style specification! Gone. My guess is that WP doesn't like the rgb and/or the non-standard margin and calls the whole string invalid. This happens with either of these being modified, doesn't have to be both.
But it gets worse. Doing a lot of research, I found references to kses.php and allowed tags. Checked the new one in 2.8.6 and 'title' in an img tag wasn't there. I added it to the list because I believe that this omission was the further cause of the entire img tag, with fully specified dimensions, border, margins, floats and file location to be reduced to <img /> in every image in the posts that I proofread that morning. Totaled 22 images in 8 posts that I had to find their locations and figure out the code to make the page back into what I had previously crafted.
Haven't been able to reproduce the entire stripping of the img tag code down to nothing... yet. Trying to reproduce it by adding in a fictitious style spec to take the place of the once-missing 'title' allow, that would cause either AtD or WP to strip it, hasn't done anything unexpected. WP strips it out but the rest is left alone. AtD strips it out but Borks my code in the process and that apparently causes WP to strip the code further when a Save is triggered.
The above scares the heck out of me enough to disable the plugin until something changes. That was a lot of work that I hadn't planned to do yesterday.