If the pixel size of the new .gif image is not the same as
the old .gif image, you can open the topic, right-click the new
image, and select Reset Size.
It's still not very fast, but it's a bit quicker than
re-importing (and if you're under source control, it's a WHOLE LOT
quicker!)
And thanks, John, for remembering that - I always forget and
have to hear about the distorted images from QA!
Elisa