Usually I leave HTML/images disabled in Mail.app. But sometimes I'd like the ability to enable them for one particular email, then disable it again. It was a bit of a pain to dig through the preferences each time this happened.
Applescript to the rescue!
tell application "Mail"
set currentState to download html attachments
if currentState = false then
set newState to true
else
set newState to false
end if
set download html attachments to newState
display dialog ¬
"Download HTML attachments set to \"" & ¬
newState & "\"." buttons {"OK"}
end tell
Pretty simple, but useful!
Mac OS X Hints
http://hints.macworld.com/article.php?story=20031022153919228