The share buttons have classes RadSocialShare and RadSocialShare_Defauld which you could style in your css file. The Icons inside the social share block has class "sshLinkItem", which could be styled also.
In addition, I could not find the attachments of mentioned by you .png files. In case the information above do not helps you, please re-attache the images in order to see your needs.
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items