MyBB Community Forums

Alright guys,so I recently added new categories/forums/tabs to my forums and when the homepage loads,48 icons are loaded(one for each forum).Now,I have already compressed each image but I think that it's still a pretty heavy load.Can somebody tell me how can I effectively combine all of these images using css sprites?

That depends on how exactly you added forum images. But basically: https://css-tricks.com/css-sprites/#article-header-id-2 - you add a div/span with background-image position based on the position of an icon on the image. {$forum['fid']} can be used for element CSS IDs/classes.