changing default image size and centring photo in post

Hi

I love this plugin, but I’m not so keen on the photos posting at 650×650 px, as I think it makes them look low quality. Is there a way to set the size of the photo I’d like and to have it centred in the post?

Also the once hourly checking doesn’t seem to be working for some reason.

Thanks

https://wordpress.org/plugins/dsgnwrks-instagram-importer/