diff -urN netpbm-10.51.00-orig/converter/other/pamrgbatopng.c netpbm-10.51.00/converter/other/pamrgbatopng.c
--- netpbm-10.51.00-orig/converter/other/pamrgbatopng.c	2006-08-19 12:12:28 +0900
+++ netpbm-10.51.00/converter/other/pamrgbatopng.c	2011-01-04 22:21:34 +0900
@@ -105,6 +105,7 @@
         infoP->height     = pamP->height;
         infoP->bit_depth  = 8;
         infoP->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+        infoP->valid     &= ~PNG_INFO_sRGB;
         
         png_init_io(pngP, ofP);