diff --git a/docs/requirements.txt b/docs/requirements.txt
index e5d60ffc..94f133fd 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -5,7 +5,7 @@ python-markdown-math==0.8
 alabaster==0.7.8
 Babel==2.3.4
 docutils==0.21.2
-imagesize==0.7.1
+imagesize==1.4.1
 Jinja2==2.11.3
 MarkupSafe==0.23
 Pygments==2.7.4