diff --git a/include/osg/Image b/include/osg/Image
index 3a90175ea..663761c80 100644
--- a/include/osg/Image
+++ b/include/osg/Image
@@ -68,6 +68,10 @@
 #endif
 
 #if defined(OSG_GLES1_AVAILABLE) || defined(OSG_GLES2_AVAILABLE) || defined(OSG_GLES3_AVAILABLE) || defined(OSG_GL3_AVAILABLE)
+    #define GL_ALPHA4               0x803B
+    #define GL_ALPHA8               0x803C
+    #define GL_ALPHA12              0x803D
+    #define GL_ALPHA16              0x803E
     #define GL_BITMAP               0x1A00
     #define GL_COLOR_INDEX          0x1900
     #define GL_INTENSITY12          0x804C