diff --git a/Dockerfile b/Dockerfile
index 4287f6d..82b04bf 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,6 +6,7 @@ RUN set -ex; \
 	apt-get update; \
 	apt-get install -y \
 		libsqlite3-dev \
+		libpng-dev \
 		unzip \
 	; \
 	rm -rf /var/lib/apt/lists/*; \