how to reproduce

• Go to the demo https://demo.ametys.org/nightly-intranet-cms/www/index.html demo site
• go to the "integrator" tab, "graphic charter workshop" button
• load a background image.
• save and go live
• go to the back office admin (https://demo.ametys.org/nightly-intranet-cms/_admin/index.html)
• go to the Administration tab, skin button
• duplicate the demo skin
• Create a site and associate the skin with it
• go to the back office of the new site
• go to the "integrator" tab, "skin workshop" button
• edit title
• save and go into production.
  Locally loaded images are not loaded after duplication.
  We lose all the images