diff -upr dillo-2.1.1.orig/src/png.c dillo-2.1.1/src/png.c
--- dillo-2.1.1.orig/src/png.c	2010-01-23 04:09:50.000000000 +0200
+++ dillo-2.1.1/src/png.c	2010-01-23 04:12:34.000000000 +0200
@@ -345,7 +345,7 @@ static void Png_write(DilloPng *png, voi
             return;            /* need MORE data */
          }
          /* check the image signature - DON'T update ipbufstart! */
-         if (!png_check_sig(png->ipbuf, DATASIZE)) {
+         if (png_sig_cmp(png->ipbuf, 0, DATASIZE)) {
             /* you lied to me about it being a PNG image */
             MSG_WARN("\"%s\" is not a PNG file.\n", URL_STR(png->url));
             png->state = IS_finished;