"width" parameter is lost when editing in WYSIWYG

To reproduce:

• Add the following in a wiki page

  [[image:image.png||width="20%"]]

• Upload an attachment named image.png on that page
• Verify that the image is displayed with the 20% resize
• Click edit to go either in inplace editing or standalone editing
• Notice that the image is no longer displayed using 20% and click source and notice that the width parameter has disappeared.
• Save