The same goes for CSS files. I have seen many sites that have 5 or 6 external style sheets linked to their pages, all controlling a certain aspect of the structure or content of their site. I try to keep one global CSS external file to control as much as possible, and just add individual styles to the actual page, which if you have your global CSS file impemented right, the individual styles are very few, and non conflicting.
Photos will eat some bandwidth as well, and if you plan on having pages that display several models of phones, or something to that affect, then you may want to just display thumbnails on your pages, that when clicked can be shown at full size, rather than adding all the full size pictures to your pages that will all load when that particular page is called upon.
These are just some considerations to think about when you start implementing features to your site, and just remember that people will visit your site for the content, not for fancy graphics, animations, and the rest of the junk that makes web pages load slow.
Hope this helps,p.s.
give me a link to your site so I can check out your content, and I will consider adding it to the related catagory that I have on my web sites, if you are interested of course.