Resolved.
The problem is the plugin RedactorJS.
When you insert an image and try to edit it, you can not first insert it into the desired position and you must do so by editing the html code; if you try to edit the title of the image, you modify the ALT.
I replaced another text editor and now works correctly.
I recommend you try to do checking RedactorJS selecting as default and try to edit an image editor.
I have tried several text editors and works best and offers more functionality is the JCE editor. You can create multiple profiles and layauts user group; select which folders and files you can access the various user groups and visually, if they select the layaut "mobile" is just perfect.
If you want to comment on my experience with the JCE editor, do not hesitate to contact me.
Thank you very much.