Is there an object style option for automatically centering a frame relative to the text frame it is placed into?
You may need an object style for the frames if the frames are all the same and may include borders, text wrap, frame fitting options, etc.
But if you are making the graphics inline objects on their own line in the text, you also need a paragraph style. The paragraph style may include center alignment, auto leading, space above, and space below.
Is that what you are doing?