fix url for https

hartmann-foto-documentation-frontend/lib/pages/customer/picture_widget.dart

@@ -158,6 +158,16 @@ class _PictureWidgetState extends State<PictureWidget> {
             headers: {cred.name: cred.value},
             dto.normalSizeUrl,
             fit: BoxFit.contain,
+            loadingBuilder: (context, child, loadingProgress) {
+              if (loadingProgress == null) return child;
+              return Center(
+                child: CircularProgressIndicator(
+                  value: loadingProgress.expectedTotalBytes != null
+                      ? loadingProgress.cumulativeBytesLoaded / loadingProgress.expectedTotalBytes!
+                      : 0,
+                ),
+              );
+            },
           ),
         ),
       ),