Can I use figures from my article on my website after it is accepted but before being published, if I publish open access and retain the copyright?
(b) reuse figures [...] created by the Author(s) and contained in the Contribution in [...] other works created by them.


does IMHO cover your pictures. 

However, depending on you legislation you may need to get approval (legally speaking: a license) by your coauthors.  


IIRC in the US each coauthor can excercise the copyright independent of the other coauthors (please correct me if I'm wrong) 
but e.g. in Germany all coauthors hold the copyright together, and must act together. 


I guess that already single figures are works of their own and thus may only have a subset of the paper's coauthors as authors (but IANAL). But IMHO figures in scientific papers still frequently have multiple coauthors: in analogy to what constitutes authorship for a paper, I'd say that everyone who had an important contribution to the figure is coauthor of the figure.  

Examples:  


A suggests that a hexbinplot is more appropriate than the current pseudo-3d scatter plot. B accordingly changes the figure => I'd say both A and B are coauthors of the final figure. 
A result plot showing a model and the experimental data: experimental design &amp; measurements by A, theoretical bounds for models by B, and modeling of the experimental data &amp; plotting of all into one figure by C => IMHO makes 3 coauthors.


Note: things may be even more complicated as e.g. in Germany the right for secondary publication according to §38 UrhG refers to the authors, while the commercial rights are typically with the employer.  

Practically speaking I guess it is easiest to ask all coauthors of the paper (and if relevant your employer) for permission to re-use the paper or parts of it on the web site. I'd anyways consider piecemeal asking of some coauthors every time you want to put another figure on your blog as impolite.