def annotate_img(image, service, layers, environ, query_extent, **kw):

    # Required opacity of watermark
    opacity = float(0.5)

    # Get path to watermark png
    wm_path = Image.open(os.path.join(os.path.dirname(__file__), 'watermark_256.png'))

    # Grab tile and Convert to RGBA
    img = image.as_image()
    if img.mode != 'RGBA':
        img = img.convert('RGBA')

    # Create new RGBA image for watermark
    wm = Image.new('RGBA', img.size, (0,0,0,0))
    wm.paste(wm_path)

    # Adjust opacity of watermark
    alpha = wm.split()[3]
    alpha_c = ImageEnhance.Brightness(alpha).enhance(opacity)
    wm.putalpha(alpha_c)

    # Create new composite image using the wm as a mask
    compo = Image.composite(wm, img, wm)
    final_img = Image.new('RGBA', img.size, (0,0,0,0))
    final_img.paste(compo)

    return ImageSource(final_img, image.image_opts)

self.im.paste(im, box)
ValueError: images do not match

self.im.paste(im, box, im)