Click into your File Manager module

Open up your computer documents and drag and drop the images you'd like into the file manager

Alternatively, click the 6th icon from the left (it looks like a floppy disc with a plus sign)

This will open your computer documents - you can click on the appropriate folder which contains your images you'd like added to the file manager. Select an image/images and click the 'Open' button

Your new image will appear in the file manager - feel free to add it to a folder by dragging and dropping it. You can right click on the white space to create a new folder