Full text image float - need to center horizontally on the width

Hi,
Am using T3 BS3 Blank template and need to center the Full Text Image horizontally.

We've turned FLOAT on both intro and full text images to NONE in the OPTIONS for articles but we're still not getting the images to center on the width.

Using: Joomla 3.4.1 and latest T3 BS3 Blank v2.2.0

Any advice would be really appreciated.

Thanks,
Terry.