diff --git a/docs/doxygen/extra_stylesheet.css b/docs/doxygen/extra_stylesheet.css
index cd9d17f2b6..5f98bfab2d 100644
--- a/docs/doxygen/extra_stylesheet.css
+++ b/docs/doxygen/extra_stylesheet.css
@@ -12,6 +12,7 @@ div.appearance table {
 }
 div.appearance img {
     margin: 0.5em;
+    filter: none !important;
 }
 div.appearance .caption {
     font-style: italic;