fix null merchant image crash

@@ -237,21 +237,22 @@ extension UIImage {
             
         } else {
             //No cache, so create new one and set image
-            let url = URL(string: urlString)
-            URLSession.shared.dataTask(with: url!, completionHandler: { (data, response, error) in
-                if let error = error {
-                    print(error)
-                    return
-                }
-
-                DispatchQueue.main.async(execute: {
-                    if let downloadedImage = UIImage(data: data!) {
-                        imageCache.setObject(downloadedImage, forKey: urlString as NSString)
-                        completion(downloadedImage)
+            if let url = URL(string: urlString) {
+                URLSession.shared.dataTask(with: url, completionHandler: { (data, response, error) in
+                    if let error = error {
+                        print(error)
+                        return
                     }
-                })
 
-            }).resume()
+                    DispatchQueue.main.async(execute: {
+                        if let downloadedImage = UIImage(data: data!) {
+                            imageCache.setObject(downloadedImage, forKey: urlString as NSString)
+                            completion(downloadedImage)
+                        }
+                    })
+
+                }).resume()
+            }
         }
     }
 }