Fix missing/incorrect image file extension on download. See http://henrik.nyh.se/2008/11/extension-action for details.

Ensure Image Extension.scpt

on adding folder items to myFolder after receiving myFiles
	repeat with myFile in myFiles
		
		set myPath to (POSIX path of myFile)
		set myType to do shell script "file --mime-type -br " & (quoted form of myPath)
		
		if myType is "image/jpeg" and myPath does not end with ".jpg" and myPath does not end with ".jpeg" then
			set newExtension to ".jpg"
		else if myType is "image/gif" and myPath does not end with ".gif" then
			set newExtension to ".gif"
		else if myType is "image/png" and myPath does not end with ".png" then
			set newExtension to ".png"
		else
			set newExtension to null
		end if
		
		tell application "Finder"
			
			if newExtension is not null then
				set name of myFile to (name of myFile) & newExtension
			end if
			
		end tell
	end repeat
end adding folder items to