Hi,
Like I said in my first message : I don't know.
I don't know, it depends on the popup system you use.
Your template can override it, because Joomla propose his own popup system for images so everybody can use/override it.
It can't change my mind because I do not know anything about your current template or the used popup system.
So, because I don't know anything about it, I do not know.
But if you want an answer : yes there is a way which need time, knowledge, analysis and development.
Like we said quite often : everything is possible with time and patience.
Regards,