Replacing all textures in a project?

Hi all,

Developing a game for mobile and have recently become aware that almost all of the textures we've been using up until this point are roughly 20 times the size we need them to be. I've asked our art guy to get me some smaller versions and have made sure that all materials are in the same location in preparation, however there are many instances where I have referenced and connected textures manually through the inspector and switch through them in code.

My question is, is there any way (trick/hack/script) to swap out my current textures with new ones and have everything maintain reference to it? I'd really like to not have to go back through everything in every scene and manually reconnect it (though I guess that would teach me to never make this mistake again)

Thanks!