I think you need to create a custom button to achieve this.

 

1.  Create a custom button and add the onclick event to this. When the users click the button, we open a pop-up window.

 

2. In the pop-up window, we list all the images, media and document with your custom tool.

 

3. When the users select the images, media and document, we paste the content into the editor and close the pop-up window.

 

Hope it helps.