diff --git a/src/bin/jp2/convert.c b/src/bin/jp2/convert.c
index fa02e31c..1607232d 100644
--- a/src/bin/jp2/convert.c
+++ b/src/bin/jp2/convert.c
@@ -2021,7 +2021,7 @@ int imagetopnm(opj_image_t * image, const char *outfile, int force_split)
     int *red, *green, *blue, *alpha;
     int wr, hr, max;
     int i;
-    unsigned int compno, ncomp;
+    unsigned int compno, ncomp, ui;
     int adjustR, adjustG, adjustB, adjustA;
     int fails, two, want_gray, has_alpha, triple;
     int prec, v;
@@ -2029,6 +2029,18 @@ int imagetopnm(opj_image_t * image, const char *outfile, int force_split)
     const char *tmp = outfile;
     char *destname;
 
+    fails = 0;
+    ncomp = image->numcomps;
+    for (ui = 0; ui < ncomp; ++ui) {
+        if (image->comps[ui].data == NULL) {
+            fprintf(stderr, "imagetopnm data[%u] == NULL\n", ui);
+            fails = 1;
+        }
+    }
+    if (fails) {
+        return 1;
+    }
+
     alpha = NULL;
 
     if ((prec = (int)image->comps[0].prec) > 16) {
diff --git a/src/bin/jp2/opj_decompress.c b/src/bin/jp2/opj_decompress.c
index a28a194b..8260ecba 100644
--- a/src/bin/jp2/opj_decompress.c
+++ b/src/bin/jp2/opj_decompress.c
@@ -538,12 +538,25 @@ static int infile_format(const char *fname)
         return ext_format;
     }
 
-    s = fname + strlen(fname) - 4;
+    s = fname + strlen(fname) - 1;
 
-    fputs("\n===========================================\n", stderr);
+#ifdef WIN32
+    while (s > fname && (*s != '.' && *s != '\\')) {
+        --s;
+    }
+#else
+    while (s > fname && (*s != '.' && *s != '/')) {
+        --s;
+    }
+#endif
+    if (*s != '.') {
+        s = "";
+    }
+
+    fputs("\n===============================================\n", stderr);
     fprintf(stderr, "The extension of this file is incorrect.\n"
-            "FOUND %s. SHOULD BE %s\n", s, magic_s);
-    fputs("===========================================\n", stderr);
+            "    FOUND '%s'. SHOULD BE '%s'", s, magic_s);
+    fputs("\n===============================================\n", stderr);
 
     return magic_format;
 }