change bg to white

lib/src/giphy_attachment.dart

@@ -31,9 +31,7 @@ class GiphyAttachment extends StatelessWidget {
       );
     }
 
-    return Container(
+    return Column(
-      color: Colors.white,
-      child: Column(
       mainAxisSize: MainAxisSize.min,
       crossAxisAlignment: CrossAxisAlignment.stretch,
       children: <Widget>[
@@ -90,7 +88,6 @@ class GiphyAttachment extends StatelessWidget {
             message: message,
           ),
       ],
-      ),
     );
   }
 }

lib/src/message_widget.dart

@@ -512,12 +512,12 @@ class _MessageWidgetState extends State<MessageWidget> {
             widget.message,
             attachment,
           );
-          return wrapAttachmentWidget(context, attachmentWidget);
+          return wrapAttachmentWidget(context, attachmentWidget, attachment: attachment);
         })?.toList() ??
         [];
   }
 
-  Padding wrapAttachmentWidget(BuildContext context, Widget attachmentWidget) {
+  Padding wrapAttachmentWidget(BuildContext context, Widget attachmentWidget, {Attachment attachment}) {
     return Padding(
       padding: EdgeInsets.only(
         bottom: 4,
@@ -526,7 +526,7 @@ class _MessageWidgetState extends State<MessageWidget> {
         onTap: () => retryMessage(context),
         onLongPress: () => onLongPress(context),
         child: Material(
-          color: _getBackgroundColor(),
+          color: attachment?.type == 'giphy' ? Colors.white : _getBackgroundColor(),
           clipBehavior: Clip.hardEdge,
           shape: widget.attachmentShape ??
               widget.shape ??