diff --git a/CHANGES b/CHANGES
index ba2f15cb9..669c29062 100644
--- a/CHANGES
+++ b/CHANGES
@@ -18,6 +18,7 @@ Bugs fixed
 
 * LaTeX: Remove extraneous space after author names on PDF title page (refs: #6004)
 * #6046: LaTeX: ``TypeError`` is raised when invalid latex_elements given
+* #6019: imgconverter: Including multipage PDF fails
 
 Testing
 --------
diff --git a/sphinx/ext/imgconverter.py b/sphinx/ext/imgconverter.py
index 79755d351..b0b379936 100644
--- a/sphinx/ext/imgconverter.py
+++ b/sphinx/ext/imgconverter.py
@@ -66,9 +66,9 @@ class ImagemagickConverter(ImageConverter):
         # type: (unicode, unicode) -> bool
         """Converts the image to expected one."""
         try:
-            if _from.lower().endswith('.gif'):
-                # when target is GIF format, pick the first frame
-                _from += '[0]'
+            # append an index 0 to source filename to pick up the first frame
+            # (or first page) of image (ex. Animation GIF, PDF)
+            _from += '[0]'
 
             args = ([self.config.image_converter] +
                     self.config.image_converter_args +