Dear Ning,
it is more difficult to have both share and independent images folder.
You can either share everything or have a totally independe image folder.
If you want to have a totally independent images directory, you can find a sample in the tutorial video CP-05.
www.jms2win.com/tutorial#jms12x-CP-05
Create an independent directory can be done when you replicate a website.
You can create a JMS template like in CP-05 and put
- domain = {site_url}/multisites/{site_id}
- New table prefix = {site_id}_
- Deploy directory = {site_dir}
- media folders = images
- images folders = images/stories
or you can go in "folders and files" where you select the action "copy" for the "images" folder.
If inside the specific images folder you want have sub-direcory like "common" or "shared" folder, you will need to create manually a Symbolic Link like JMS is doing with other directories. You will need a SSH prompt and use a unix command like "ln -s".
See the unix "man"ual to get more detail on this unix "ln -s" command.