imagesToKeynote.applescript

tell application "Finder"
    set folderFiles to (choose folder with prompt "Please select directory.")
    set file_list to name of every file of entire contents of folderFiles
end tell

tell application "Keynote"
    activate
    tell the front document
        repeat with fileName in file_list
            set the newSlide to make new slide
            set the base slide of the newSlide to master slide "MASTER-LAYER-NAME"
            set thisPlaceholderImageItem to image 1 of newSlide
            set file name of thisPlaceholderImageItem to alias ((folderFiles as string) & fileName)
        end repeat
    end tell
end tell