Images shared folder

I have main domain and a subdomain. its addresses are like this
thebannutimes.com
and
en.thebannutimes.com
I have installed WordPress separately on them and use separate themes. But actually the subdomain is the English version of my newspaper. Mostly the featured images are same but I have to upload them separately. I wish to save disk space.
Is there any plugin the gives me an option so that I can use the same images for both the versions.