How does one try to make a journal cover? Though fewer and fewer scientists actually read dead-tree editions of journals, being featured on a journal cover is still a nice way to highlight your paper to a large community, and is usually considered a great recognition of one’s work. So, how does one go about getting on a journal cover? If you feel you have extraordinarily attractive graphics, do you submit them for consideration to the editor? Or is it useless, and should only be done when explicitly asked (or suggested) by the editor?
I emailed the editor and suggested I had a beautiful and relevant graphic for a special issue. That worked. 

Edit: Image attached. Also, note that I did go about it incorrectly, but it worked anyway. I emailed the editors when I submitted my paper. I should have waited until it was accepted.