diff --git a/build-unit-test-docker.sh b/build-unit-test-docker.sh
index 644189d..2e86cf5 100755
--- a/build-unit-test-docker.sh
+++ b/build-unit-test-docker.sh
@@ -141,6 +141,7 @@
     libevdev-dev \
     libevdev2-dbgsym \
     libjpeg-dev \
+    libpng-dev \
     sudo \
     curl \
     git \
@@ -202,7 +203,7 @@
 cd libvncserver && \
 mkdir build && \
 cd build && \
-cmake ${CMAKE_FLAGS[@]} -DWITH_PNG=OFF .. && \
+cmake ${CMAKE_FLAGS[@]} .. && \
 make -j$(nproc) && \
 make install