Set up file and image uploads to S3

Is it possible to change S3 service providers?

I’d like to know if there will be any issues if I try to change S3 service providers, ignoring the issue of already uploaded images. I don’t really have any major issues with this since the site isn’t up and running yet; I’m still developing it.

Is it possible to save the images locally and then activate S3 again with the new service provider?