diff --git a/docs/requirements.txt b/docs/requirements.txt
index 2211dd5..c77dd1e 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -2,3 +2,4 @@ sphinx ~= 5.3
 sphinx_rtd_theme ~= 1.1
 myst-parser ~= 0.18
 linkify-it-py ~= 2.0
+standard-imghdr