diff --git a/ext/gd/gd.c b/ext/gd/gd.c
index 4731eff74111c..5af2d4a5152bb 100644
--- a/ext/gd/gd.c
+++ b/ext/gd/gd.c
@@ -118,9 +118,9 @@ static void php_image_filter_pixelate(INTERNAL_FUNCTION_PARAMETERS);
 static void php_image_filter_scatter(INTERNAL_FUNCTION_PARAMETERS);
 
 /* End Section filters declarations */
-static gdImagePtr _php_image_create_from_string(zend_string *Data, char *tn, gdImagePtr (*ioctx_func_p)(gdIOCtxPtr));
-static void _php_image_create_from(INTERNAL_FUNCTION_PARAMETERS, int image_type, char *tn, gdImagePtr (*func_p)(FILE *), gdImagePtr (*ioctx_func_p)(gdIOCtxPtr));
-static void _php_image_output(INTERNAL_FUNCTION_PARAMETERS, int image_type, char *tn);
+static gdImagePtr _php_image_create_from_string(zend_string *Data, const char *tn, gdImagePtr (*ioctx_func_p)(gdIOCtxPtr));
+static void _php_image_create_from(INTERNAL_FUNCTION_PARAMETERS, int image_type, const char *tn, gdImagePtr (*func_p)(FILE *), gdImagePtr (*ioctx_func_p)(gdIOCtxPtr));
+static void _php_image_output(INTERNAL_FUNCTION_PARAMETERS, int image_type, const char *tn);
 static gdIOCtx *create_stream_context(php_stream *stream, int close_stream);
 static gdIOCtx *create_output_context(zval *to_zval, uint32_t arg_num);
 static int _php_image_type(zend_string *data);
@@ -1424,7 +1424,7 @@ static int _php_image_type(zend_string *data)
 /* }}} */
 
 /* {{{ _php_image_create_from_string */
-gdImagePtr _php_image_create_from_string(zend_string *data, char *tn, gdImagePtr (*ioctx_func_p)(gdIOCtxPtr))
+gdImagePtr _php_image_create_from_string(zend_string *data, const char *tn, gdImagePtr (*ioctx_func_p)(gdIOCtxPtr))
 {
 	gdImagePtr im;
 	gdIOCtx *io_ctx;
@@ -1529,7 +1529,7 @@ PHP_FUNCTION(imagecreatefromstring)
 /* }}} */
 
 /* {{{ _php_image_create_from */
-static void _php_image_create_from(INTERNAL_FUNCTION_PARAMETERS, int image_type, char *tn, gdImagePtr (*func_p)(FILE *), gdImagePtr (*ioctx_func_p)(gdIOCtxPtr))
+static void _php_image_create_from(INTERNAL_FUNCTION_PARAMETERS, int image_type, const char *tn, gdImagePtr (*func_p)(FILE *), gdImagePtr (*ioctx_func_p)(gdIOCtxPtr))
 {
 	char *file;
 	size_t file_len;
@@ -1759,7 +1759,7 @@ PHP_FUNCTION(imagecreatefromtga)
 #endif
 
 /* {{{ _php_image_output */
-static void _php_image_output(INTERNAL_FUNCTION_PARAMETERS, int image_type, char *tn)
+static void _php_image_output(INTERNAL_FUNCTION_PARAMETERS, int image_type, const char *tn)
 {
 	zval *imgind;
 	char *file = NULL;
@@ -3001,8 +3001,7 @@ static void php_imagechar(INTERNAL_FUNCTION_PARAMETERS, int mode)
 {
 	zval *IM;
 	zend_long X, Y, COL;
-	char *C;
-	size_t C_len;
+	zend_string *C;
 	gdImagePtr im;
 	int ch = 0, col, x, y, i, l = 0;
 	unsigned char *str = NULL;
@@ -3014,7 +3013,7 @@ static void php_imagechar(INTERNAL_FUNCTION_PARAMETERS, int mode)
 		Z_PARAM_OBJ_OF_CLASS_OR_LONG(font_obj, gd_font_ce, font_int)
 		Z_PARAM_LONG(X)
 		Z_PARAM_LONG(Y)
-		Z_PARAM_STRING(C, C_len)
+		Z_PARAM_STR(C)
 		Z_PARAM_LONG(COL)
 	ZEND_PARSE_PARAMETERS_END();
 
@@ -3023,9 +3022,9 @@ static void php_imagechar(INTERNAL_FUNCTION_PARAMETERS, int mode)
 	col = COL;
 
 	if (mode < 2) {
-		ch = (int)((unsigned char)*C);
+		ch = (int)((unsigned char)*ZSTR_VAL(C));
 	} else {
-		str = (unsigned char *) estrndup(C, C_len);
+		str = (unsigned char *) estrndup(ZSTR_VAL(C), ZSTR_LEN(C));
 		l = strlen((char *)str);
 	}
 
@@ -3407,6 +3406,7 @@ static void php_imagettftext_common(INTERNAL_FUNCTION_PARAMETERS, int mode)
 
 	PHP_GD_CHECK_OPEN_BASEDIR(fontname, "Invalid font filename");
 
+	// libgd note: Those should return const char * ideally, but backward compatibility ..
 	if (EXT) {
 		error = gdImageStringFTEx(im, brect, col, fontname, ptsize, angle, x, y, str, &strex);
 	} else {