diff --git a/v4l2/rgb2fimg.c b/v4l2/rgb2fimg.c
index fcb10ad..269b53c 100644
--- a/v4l2/rgb2fimg.c
+++ b/v4l2/rgb2fimg.c
@@ -24,7 +24,12 @@ static unsigned short		modz;
  *	check in image sizes are correct
  */
 if ( d->width != w*2 || d->height != h*2 ) {
-	fprintf(stderr, "%s : dimension error\n", __func__);
+	fprintf(stderr, "%s: dimension error\n", __func__);
+	fprintf(stderr, "\tw = %d   h = %d\n", w, h);
+	fprintf(stderr, "\tdest image is %dx%d\n", d->width, d->height);
+#if MUST_ABORT
+	abort();
+#endif
 	return -2;
 	}