handle Photoshop chunks which can't be processed

src/PIL/JpegImagePlugin.py

@@ -101,16 +101,16 @@ def APP(self, marker):
         # markers appear in the correct sequence.
         self.icclist.append(s)
     elif marker == 0xFFED and s[:14] == b"Photoshop 3.0\x00":
+        # Process this marker only if previous were empty
+        if not self.info.get("photoshop"):
             # parse the image resource block
             offset = 14
             photoshop = {}
             while s[offset : offset + 4] == b"8BIM":
+                try:
                     offset += 4
                     # resource code
-            try:
                     code = i16(s, offset)
-            except struct.error:
-                break
                     offset += 2
                     # resource name (usually empty)
                     name_len = i8(s[offset])
@@ -131,6 +131,8 @@ def APP(self, marker):
                     photoshop[code] = data
                     offset += size
                     offset += offset & 1  # align
+                except struct.error:
+                    break  # no sufficient data
             self.info["photoshop"] = photoshop
 
     elif marker == 0xFFEE and s[:5] == b"Adobe":