Edit group masthead, can not add picture then change it.

Create a group, and then edit the mast e3ad and attach and image and age. Now edit again and remove the image. You can not add a new one, you select a new file after remove the old one and select save and the form just reload without saving the image attachment.

Even if you cancel the edit and edit agian, you can not attache a new image after memoving one.