Here’s an i09 article (http://io9.com/5832671/how-science-fiction-cover-art-got-its-pulpy-sense-of-wonder?tag=pulps – links are still broken) on early pulp magazine covers. They are VERY special. . . see?
Here’s the bit you steampunks are probably most interested in:
The Victorian aesthetic appeared from 1820-1900 and is characterized by tons of ornamentation, both in imagery and typography. Most book and magazine covers escaped excessive imagery, but faltered under cluttered typography. Captions often accompanied images to narrate the moment of action rather than allowing the image to speak for itself. Images portrayed a single moment in the story meant to captivate passersby with feelings of adventure and excitement. Actions and poses were stiff and often awkward. Color was expensive, and not commonly seen until 1900.
You’ll want to scan through the pictures for yourself, so here’s that address again.