A good book speaks for itself and conjures up its own images in the reader's mind. A good book, however, still needs a good cover.
Literary magazines today rely on shorter content, especially online magazines, because reading long paragraphs isn't as easy on the web. But almost every lit mag benefits from visual material.
Online lit mags with no cover images, branding, and/or web design seem...too plain. Unprofessional websites are a huge turnoff for me when I'm seeking new places to send my work because I want my work to not only be published, but also presented.
Thus, I don't think that visual/literary pairings always work, but I think every lit mag needs to explore visual ways to presentation. Some of the best, most memorable lit mags and sites--take a look at Synaesthesia's website and any of their issues--incorporate visual features.
The bottom line is that lit mags often need art. Although Duotrope doesn't list art as a separate 'market,' I have a process for finding and submitting to markets that has worked well for me. This does require a Duotrope subscription, which I highly recommend to keep track of all writerly and artistic submissions: