1 files changed, 2 insertions, 1 deletions
diff --git a/lib/libpgm1.c b/lib/libpgm1.c
index 57344c16..de5aedde 100644
--- a/lib/libpgm1.c
+++ b/lib/libpgm1.c
@@ -167,7 +167,8 @@ pgm_readpgminit(FILE * const fileP,
         break;
 
     default:
-        pm_error("bad magic number - not a Netpbm file");
+        pm_error("bad magic number 0x%x - not a PPM, PGM, PBM, or PAM file",
+                 realFormat);
     }
     validateComputableSize(*colsP, *rowsP);
 }