(5/08 built 2.66 GHz iMac 20", 4 GB etc.) Snow Leopard 10.6.3
Safari Version 4.0.5 (6531.22.7)

When I first opened link (new window) I saw the right shift you describe.

As I usually set horiz. size of browser window to <max available, I expanded to right, a tad:
the right shift ceased as I moved the rt.-margin -->.
Then I reduced horiz. size in increments; at any abbreviated or lengthened horiz. setting, no more right-shifts happened!

Looking at w3c re BR clear="left", at
http://www.w3.org/TR...ent/graphics.html
(Note, they use ["] and not ['] in their example-prose; I used bold above, here ... lest I add-confusion about notation.

Browsing down your page . . .
Where your last sentence needs more space than image-height accommodates:
all those extra sentences appear to begin under the image and at image's left margin -- per spec. as illustrated, for this command.

Strange that it exhibited the glitch, was immediately 'corrected' just by moving out the rt. margin ... and right-shift never recurred.
(I didn't nuke cache and try clovegarden link fresh, after this first try.)
... prefer not to nuke cache as I have n+1 pages open, some of which I don't want to have reloaded with new/today's update.

hth,

I.