### Expected behavior - When switching between Visual mode and HTML mode class attributes on image should be kept consistent ### Actual behavior - Class attributes are duplicated if they are not part of the standard img class attributes: alignment and size. ### Steps to reproduce the behavior - Open the empty demo app - Add an image to the post - Switch to html mode - Add the following attribute to the img tag: `class="test"` - Switch to Visual and then back to HTML - See the attribute duplicated ##### Tested on iPhone 7, iOS 10, Aztec beta 8
