>>285
デスクトップもフォルダなのでフォルダアクションが使えました。
on adding folder items to inFolder after receiving inItems
try
set myDesktopFolder to (path to desktop) as string

tell application "Finder"
set itemCount to number of items in inItems

repeat with i from 1 to itemCount
set theAlias to item i of inItems
set theExtension to name extension of theAlias
if theExtension is "jpg" then
move theAlias to (myDesktopFolder & "jpg") as alias without replacing
end if
end repeat
end tell
end try
end adding folder items to