use VIPS_FOREIGN_PNG_FILTER_ALL in vips_pngsave_bridge

vips.h

@@ -305,7 +305,7 @@ vips_pngsave_bridge(VipsImage *in, void **buf, size_t *len, int strip, int compr
 		"strip", INT_TO_GBOOLEAN(strip),
 		"compression", compression,
 		"interlace", INT_TO_GBOOLEAN(interlace),
-		"filter", VIPS_FOREIGN_PNG_FILTER_NONE,
+		"filter", VIPS_FOREIGN_PNG_FILTER_ALL,
 		NULL
 	);
 #else
@@ -596,4 +596,4 @@ int vips_find_trim_bridge(VipsImage *in, int *top, int *left, int *width, int *h
 int vips_gamma_bridge(VipsImage *in, VipsImage **out, double exponent)
 {
   return vips_gamma(in, out, "exponent", 1.0 / exponent, NULL);
-}
+}