diff --git a/src/Avatar.php b/src/Avatar.php
index 0a1c2d4..0d2061f 100644
--- a/src/Avatar.php
+++ b/src/Avatar.php
@@ -209,12 +209,12 @@ public function toSvg($customWidth=null,$customHeight)
         $radius = ($this->width - $this->borderSize) / 2;
         $center = $this->width / 2;
         
-        if(!is_null($customWidth))
-            $this->width = $customWidth;
-        if(!is_null($customHeight))
-            $this->height = $customHeight;
+        if(is_null($customWidth))
+             $customWidth = $this->width;
+        if(is_null($customHeight))
+            $customHeight = $this->height;
 
-        $svg = '<svg xmlns="http://www.w3.org/2000/svg" width="'.$this->width.'" height="'.$this->height.'" viewBox="0 0 '.$this->width.' '.$this->height.'">';
+        $svg = '<svg xmlns="http://www.w3.org/2000/svg" width="'.$customWidth.'" height="'.$customHeight.'" viewBox="0 0 '.$this->width.' '.$this->height.'">';
 
         if ($this->shape == 'square') {
             $svg .= '<rect x="'.$x