diff --git a/amiga/os3support.h b/amiga/os3support.h
index 4db3cd4eb..c93e09a06 100644
--- a/amiga/os3support.h
+++ b/amiga/os3support.h
@@ -71,6 +71,14 @@ struct TimeVal {
 #define CompositeTags(a, ...) ((void) (a))
 #define COMP_FLOAT_TO_FIX(f) (f)
 
+/* icon.library v51 (ie. AfA_OS version) */
+#define ICONCTRLA_SetImageDataFormat        (ICONA_Dummy + 0x67) /*103*/
+#define ICONCTRLA_GetImageDataFormat        (ICONA_Dummy + 0x68) /*104*/
+
+#define IDFMT_BITMAPPED     (0)  /* Bitmapped icon (planar, legacy) */
+#define IDFMT_PALETTEMAPPED (1)  /* Palette mapped icon (chunky, V44+) */
+#define IDFMT_DIRECTMAPPED  (2)  /* Direct mapped icon (truecolor 0xAARRGGBB, V51+) */ 
+
 #endif
 
 #endif