diff -up ghostscript-8.71/jbig2dec/jbig2_image.c.jbig2-image-refcount ghostscript-8.71/jbig2dec/jbig2_image.c
--- ghostscript-8.71/jbig2dec/jbig2_image.c.jbig2-image-refcount	2010-08-05 14:55:56.417043303 +0100
+++ ghostscript-8.71/jbig2dec/jbig2_image.c	2010-08-05 14:56:46.796169065 +0100
@@ -60,15 +60,18 @@ Jbig2Image* jbig2_image_new(Jbig2Ctx *ct
 /* clone an image pointer by bumping its reference count */
 Jbig2Image* jbig2_image_clone(Jbig2Ctx *ctx, Jbig2Image *image)
 {
-	image->refcount++;
+	if (image)
+		image->refcount++;
 	return image;
 }
 
 /* release an image pointer, freeing it it appropriate */
 void jbig2_image_release(Jbig2Ctx *ctx, Jbig2Image *image)
 {
-	image->refcount--;
-	if (!image->refcount) jbig2_image_free(ctx, image);
+	if (image) {
+		image->refcount--;
+		if (!image->refcount) jbig2_image_free(ctx, image);
+	}
 }
 
 /* free a Jbig2Image structure and its associated memory */