We don't currently have any methods to do that. The social sharing/like buttons are all implemented using the recommended Javascript libraries from each provider. Each network has their own rules on how you can include a sharing button, and many don't have a method other than their Javascript buttons that is supported. We have looked into providing custom like/share buttons in the past, but it's very difficult to do and keep updated/supported as each network changes.
Sorry I don't have a better answer for you, but I hope that helps explain,
Alex
Customizing Social Share Buttons
