Once I've installed Wordpress on my domain, is it no longer possible to just upload things via FTP that I code myself, or even just images?

I've tried to upload an image and when I navigate to the address I think I've put it in via FTP, my blog throws up a 404. Any ideas, or does everything have to be controlled via Wordpress new i.e. with a new post or whatever?

That's rather odd sounding. My best guess is that you're not putting it where you think you are.

Browse the site by FTP and try to get some idea where the index or some other pictures that work are. Quite often you have to upload to a sub-folder. For example, http://myblog.com/picture.jpg might actually be somewhere like ftp://ftp.myblog.com/myblog/html/picture.jpg

Thanks JJ, that makes sense. I'll take another look...

What options do you have in the Apache config? There are options to block full URLs and use the custom style URL (E.g. mydomain.com/homepage.html won't work, but mydomain.com/homepage will). If this is the case, the URL is being passed to Wordpress and Wordpress looks at its database and can't interpret the URL, so throws out a 404, as it can't interpret the location.