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I presume he means the feature in Safari 3.0 where if you're viewing a raw image (like this) that's larger than your browser window, Safari will automagically scale the image so that the width is the same size as your browser window.

I don't know if there's a way to disable it, but you can just click once on the image to make safari display the image in "actual size" instead of scaled.
 
I prefer it to resize the picture to fit to screen.

Safari 2 never had the option to downsize it, so if it was a big picture you'd have to drag it to the desktop to see it all.
 
I've always preferred to not have it auto downscale...there must be a way to turn it off
 
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