I've subdomains to my site the following

Language domain names

en.ice-os.com

ja.ice-os.com

mtrn.ice-os.com

zing.ice-os.com

Mercurial

hg.ice-os.com

Images

images.ice-os.com

how do i access images in the other subdomains from say en.ice-os.com

inside a relative way without having needing to type full path?

Relative host names isn't a feature the the URL specs has ever supported so regrettably there's no method for you to really accomplish this in HTML.

My only suggestion is to produce a single shared assets domain for example assets.ice-os.com and employ that across all of your sites.

When confronted with relative URIs, you need to clearly condition the part you need to change and everything right from it.

Within this situation, the very first section left from the left most bit that's altering may be the plan, so use a plan relative URI.

//www.example.com/foo/bar/

That could save you http:, however, you can't save anything further.