Ask for a question about PHP multi-site paths

Ask a question about the PHP multisite path
The site structure is as follows
Root
|--images
|--b
|--c

Site master domain Root.com Then there are n domains such as B.Com c.com
B.Com pointing to directory B c.com pointing to directory C

Server Environment Window + IIS
How can the B.Com c.com program be able to invoke the images in the images folder? Exclude the method of enabling a domain name as the resource domain name separately

The server environment can be replaced with the last resort of Window+apache/nginx. The server can be replaced with a Linux system (the cost of replacing the system is very large and can be replaced without replacing it.) Involves a lot of extra development of desk soft issues)

Hope that the master can enlighten. How can you implement the above things. If the master feel simple, only need to give a thought and the relevant learning materials address can ~ not much. Additional points can be added

------Solution--------------------
IIS in IIS Manager all sites right--virtual directory--Create a virtual directory images point to [d]:/root/images

Apache Set up virtual directory
Alias/images "[D]:/root/images"

Nginx does not know

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