diff --git a/src/image.c b/src/image.c
index 41eeebff36e..34936977a40 100644
--- a/src/image.c
+++ b/src/image.c
@@ -23,6 +23,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 #include <fcntl.h>
 #include <math.h>
 #include <unistd.h>
+#include <stdlib.h>
 
 /* Include this before including <setjmp.h> to work around bugs with
    older libpng; see Bug#17429.  */