diff --git a/CMakeLists.txt b/CMakeLists.txt
index 691e234aed..5e8726d081 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -383,7 +383,7 @@ if (NOT EXPAT_FOUND)
     set(EXPAT_LIBRARIES expat)
 endif ()
 
-find_package(PNG REQUIRED)
+find_package(PNG)
 
 find_package(OpenGL REQUIRED)