Use plugin method directly when saving PDFs (#9547)

Author: radarhere

src/PIL/PdfImagePlugin.py

@@ -148,10 +148,14 @@ def _write_image(
             strip_size=math.ceil(width / 8) * height,
         )
     elif decode_filter == "DCTDecode":
-        Image.SAVE["JPEG"](im, op, filename)
+        from . import JpegImagePlugin
+
+        JpegImagePlugin._save(im, op, filename)
     elif decode_filter == "JPXDecode":
+        from . import Jpeg2KImagePlugin
+
         del dict_obj["BitsPerComponent"]
-        Image.SAVE["JPEG2000"](im, op, filename)
+        Jpeg2KImagePlugin._save(im, op, filename)
     else:
         msg = f"unsupported PDF filter ({decode_filter})"
         raise ValueError(msg)