Can't post images,

I don’t know whats happened but in the last month or two when I’ve busy with other stuff and my site sitting mostly unattended, suddenly it won’t allow me to post images, no matter what I try.
Does anyone know what happened and how do I fix it? I have to post images, my site/business depends on it.

If I upgrade to the new version will that fix it?

If I do up grade what risks do I run to the site, changes etc, will it destroy the site, or lose data?.

My site is http://www.enfieldresource.com

Thanks for any help, I’m more than a bit concerned,\cheers Roger