diff --git a/docs/assets/css/docusaurus.scss b/docs/assets/css/docusaurus.scss
index 652dfee6..7c53a682 100644
--- a/docs/assets/css/docusaurus.scss
+++ b/docs/assets/css/docusaurus.scss
@@ -52,7 +52,7 @@
 
 .govuk-template--rebranded .app-masthead .govuk-grid-column-one-third-from-desktop {
   @media (min-width: 48.125em) {
-    background-image: url('https://defra.github.io/interactive-map/images/hero.jpg');
+    background-image: url('https://defra.github.io/interactive-map/images/hero.png');
     background-repeat: no-repeat;
     background-position: center bottom;
     background-size: 220px;
diff --git a/docs/assets/images/hero.jpg b/docs/assets/images/hero.jpg
deleted file mode 100644
index 06cbec1e..00000000
Binary files a/docs/assets/images/hero.jpg and /dev/null differ
diff --git a/docs/assets/images/hero.png b/docs/assets/images/hero.png
new file mode 100644
index 00000000..f1e28aec
Binary files /dev/null and b/docs/assets/images/hero.png differ