The graphics are shared under a Creative Commons Attribution-NonCommercial-NoDerivatives licence. This means they can be freely shared as long as a few conditions are met.
Firstly, they must remain unaltered – this includes the cropping off of watermarks/credit on the graphics, or cropping out other parts of the graphic. Secondly, they cannot be used for commercial purposes without prior permission. Finally, attribution to Compound Interest must be given clearly when re-sharing the graphics, and the attribution should also include a link back to the post containing the graphic.