Show a preview of an uploaded image before selecting it on the WYSIWYG image selector

Steps to reproduce

• Edit a page using WYSIWYG editor
• On the WYSIWYG toolbar click on the image icon to upload an image
• On the upload tab, click on the "Browse" button to select the image to be uploaded and click on the "Upload" button
• Notice what happen after

Current behavior :

• A notification is displayed on the bottom of the page to inform the user that the image was uploaded successfully
• The uploaded file is still visible on the file input
• Only the last uploaded image can be selected

see screenshot :

Expected behavior :

Once the upload is done it can be good to have a small preview of the image as a visual confirmation that the upload of the correct image is done and also to have the possibility to select from all the images that have been uploaded before hitting the "Select" button.