diff --git a/plugins/poll/assets/stylesheets/common/poll.scss b/plugins/poll/assets/stylesheets/common/poll.scss
index 0ebd7355b2b..1f8e6864464 100644
--- a/plugins/poll/assets/stylesheets/common/poll.scss
+++ b/plugins/poll/assets/stylesheets/common/poll.scss
@@ -29,6 +29,11 @@ div.poll {
     padding: 0.5em 0.7em 0.7em 0.5em;
   }
 
+  img {
+    max-width: 100% !important; /* needed to override internal styles */
+    height: auto;
+  }
+
   .button {
     display: inline-block;
     padding: 6px 12px;