Pages background

my site is grm.asia

the theme i used is http://www.wp-templates.com/photo-blog.html

all the pages in the site are affected by the problem. all these pages are in the home page top menu. click the round thing in the top left to see the menu if you dont see it immediately.

the footer of the page starts where it says ‘contact info’. aside from the white/grey area where the content is, the area around it is programmed to be black until the same line as the start of the footer.

i set the top part of the page to have an image as background. on most of the pages, the content gets longer than the image height and leaves a space in the background between the image end and the footer beginning. this space is black.

how do i change the main background to white? i dont want to change the size of the top part background image because it will take longer to load and i will have to repeat the process every time my content gets longer.

please help me find the part of the php or css to change in order to fix this problem.