diff --git a/Tests/images/string_dimension.tiff b/Tests/images/string_dimension.tiff
new file mode 100644
index 00000000000..d0b55830128
Binary files /dev/null and b/Tests/images/string_dimension.tiff differ
diff --git a/Tests/test_file_tiff.py b/Tests/test_file_tiff.py
index 2baeb6ae054..2d15de2bd56 100644
--- a/Tests/test_file_tiff.py
+++ b/Tests/test_file_tiff.py
@@ -587,6 +587,11 @@ def test_close_on_load_nonexclusive(self):
             im.load()
             self.assertFalse(fp.closed)
 
+    def test_string_dimension(self):
+        # Assert that an error is raised if one of the dimensions is a string
+        with self.assertRaises(ValueError):
+            Image.open("Tests/images/string_dimension.tiff")
+
 
 @unittest.skipUnless(sys.platform.startswith("win32"), "Windows only")
 class TestFileTiffW32(PillowTestCase):
diff --git a/src/PIL/TiffImagePlugin.py b/src/PIL/TiffImagePlugin.py
index 9fcffb74273..a927cd3ed90 100644
--- a/src/PIL/TiffImagePlugin.py
+++ b/src/PIL/TiffImagePlugin.py
@@ -1239,8 +1239,8 @@ def _setup(self):
             print("- YCbCr subsampling:", self.tag.get(530))
 
         # size
-        xsize = self.tag_v2.get(IMAGEWIDTH)
-        ysize = self.tag_v2.get(IMAGELENGTH)
+        xsize = int(self.tag_v2.get(IMAGEWIDTH))
+        ysize = int(self.tag_v2.get(IMAGELENGTH))
         self._size = xsize, ysize
 
         if DEBUG: