gifsicle: redirect stdout to /dev/null but keep stderr going to stdout

inc/functions.php

@@ -1939,13 +1939,14 @@ function DNS($host) {
 	return $ip_addr;
 }
 
-function shell_exec_error($command) {
+function shell_exec_error($command, $suppress_stdout = false) {
 	global $config, $debug;
 
 	if ($config['debug'])
 		$start = microtime(true);
 
-	$return = trim(shell_exec('PATH="' . escapeshellcmd($config['shell_path']) . ':$PATH";' . $command . ' 2>&1 && echo "TB_SUCCESS"'));
+	$return = trim(shell_exec('PATH="' . escapeshellcmd($config['shell_path']) . ':$PATH";' .
+		$command . ' 2>&1 ' . ($suppress_stdout ? '> /dev/null ' : '') . '&& echo "TB_SUCCESS"'));
 	$return = preg_replace('/TB_SUCCESS$/', '', $return);
 
 	if ($config['debug']) {

inc/image.php

@@ -321,8 +321,8 @@ class ImageConvert extends ImageBase {
 		if ($this->format == 'gif' && ($config['thumb_ext'] == 'gif' || $config['thumb_ext'] == '') && $config['thumb_keep_animation_frames'] > 1) {
 			if ($this->gifsicle) {
 				if (($error = shell_exec_error("gifsicle -w --unoptimize -O2 --resize {$this->width}x{$this->height} < " .
-					escapeshellarg($this->src . '') . " \"#0-{$config['thumb_keep_animation_frames']}\" >/dev/null -o " .
-					escapeshellarg($this->temp))) || !file_exists($this->temp))
+					escapeshellarg($this->src . '') . " \"#0-{$config['thumb_keep_animation_frames']}\" -o " .
+					escapeshellarg($this->temp), true)) || !file_exists($this->temp))
 					error('Failed to resize image!', null, $error);
 			} else {
 				if ($config['convert_manual_orient'] && ($this->format == 'jpg' || $this->format == 'jpeg'))