A couple of years ago I changed my websites upload directory to a subdomain (to images.mudfooted.com). I am now working on a major update on my website and wondering if the subdomain is actually the best option compared to a subdirectory (e.g. mudfooted.com/images). I get a lot of visitors via google images but am wondering if the hits to the images.mudfooted.com subdirectory only are not added to the mudfooted.com hits. I initially chose to use a subdirectory to increase the site loading speed.
So my question: Is it better to change the upload directory to a subdirectory or subdomain, taking loading time and SEO into account. Thanks for you help.