change multimedia libry path to outside wp-content

Hi all, by default, in the miscellaneous wordpress options, the multimedia library default library path is :
wp_content/uploads/

I am developing a 2 language site, with 2 wordpress installations
domain.com/es -> spanish language site
domain.com/en -> english language site

Id like to have both sharing a image library
domain.com/images

This can be applyed also to the next-gen-gallery

any help to get this issue?

thanks