Photo demographic targeting in Craft?
If I'm understanding you correctly, this is possible using the standard Craft Pro "locale" stuff. In addition to making text translatable, you can make Assets translatable - in which case you can upload a different image for each translated region. The appropriate asset will be used. This assumes you target each region by having a dedicated URL prefix for each (mysite.com/thailand, mysite.com/japan etc)

https://craftcms.com/docs/localization-guide