GearShop page design and layout
It's nice that you have a good database for background images. But personally -- when it comes to web layout and design -- I'm always against a static and stretchable background image. Visually it's quite disturbing when you scroll down (with computer, tablet, phone // specially with touch screen devices) and when there's something stationary (eg. big background image). Instead stationary image the whole page should flow down as-is.
Regarding stretching: If you look the page with higher resolutions than 1080p the background image looses it's details: it becomes pixel mess.
dpreview.com // the main site follows a good design: you have a pleasant background colour with a highlight on top left corner of the main layout. The pages are appealing with different devices.
My point is that I'm sure you want the pages look professional -- not cheap as you were using wordpress.com automatically generated web pages.
As an example you could take a look nasa web site http://www.nasa.gov/ which has a clever stationary image on the background. Or BBC who are relying on stationary banner on top: http://www.nasa.gov/ or these sites which all have their unique and stationary look:
National Geographic (awesome design regarding bg usage)
Firefall the Game
|Child and seal by APenza|
from Kids world
|Calatrava in Reggio Emilia by NCV|
from Your City - Telelens in the City
|Aurora's, Science and the Milky Way by man4mopar|
from My Best Photo of the Week