Tried it and it works well.
A big thank you to you for your answers and your reactivity !
With the developer tools, i can tell that the .JS file (jquery.gmPhantom.js?ver=4.4.1) of the plugin doesn’t include properly but I have other plugin that include .JS files and work on the same page.
Thanks for the answer, I checked it and my theme doesn’t miss those two lines.
Is there a way to collect the Gmedia upload pictures easily ?