Index: /trunk/Ohana/src/libfits/matrix/F_compress_M.c
===================================================================
--- /trunk/Ohana/src/libfits/matrix/F_compress_M.c	(revision 18105)
+++ /trunk/Ohana/src/libfits/matrix/F_compress_M.c	(revision 18106)
@@ -426,10 +426,12 @@
 int gfits_extension_is_compressed (Header *header) {
 
-    int has_extname, has_zimage, zimage;
-    char extname[80];
-
+    int has_extension, has_extname, has_zimage, zimage;
+    char extname[80], extension[80];
+
+    has_extension = gfits_scan (header, "XTENSION", "%s", 1, extension);
     has_extname = gfits_scan (header, "EXTNAME", "%s", 1, extname);
     has_zimage  = gfits_scan (header, "ZIMAGE", "%t", 1, &zimage);
 
+    if (has_extension && !strcmp (extension, "IMAGE")) return (FALSE);
     if (has_zimage && zimage) return (TRUE);
     if (has_extname) {