diff --git a/homeassistant/components/matrix/__init__.py b/homeassistant/components/matrix/__init__.py
index 03772630a9e6..47646a586ca5 100644
--- a/homeassistant/components/matrix/__init__.py
+++ b/homeassistant/components/matrix/__init__.py
@@ -362,7 +362,7 @@ class MatrixBot:
         for target_room in target_rooms:
             try:
                 room = self._join_or_get_room(target_room)
-                room.send_image(mxc, img)
+                room.send_image(mxc, img, mimetype=content_type)
             except MatrixRequestError as ex:
                 _LOGGER.error(
                     "Unable to deliver message to room '%s': %d, %s",