Check for -1 as well here

diff --git a/ext/gd/libgd/gd_png.c b/ext/gd/libgd/gd_png.c
index 1af49308c579fc75bc665c9efd7dd50081adc5eb..49f7cb0777228dfaf7f69d6ea1f199cbd3241642 100644 (file)
--- a/ext/gd/libgd/gd_png.c
+++ b/ext/gd/libgd/gd_png.c
@@ -515,8 +515,8 @@ void gdImagePngCtxEx (gdImagePtr im, gdIOCtx * outfile, int level, int basefilte
        /*  png_set_filter(png_ptr, 0, PNG_FILTER_NONE);  */
 
        /* 2.0.12: this is finally a parameter */
-       if (level < 0 || level > 9) {
-               php_gd_error("gd-png error: compression level must be between 0 and 9");
+       if (level != -1 && (level < 0 || level > 9)) {
+               php_gd_error("gd-png error: compression level must be 0 through 9");
                return;
        }
        png_set_compression_level(png_ptr, level);