I personally don't think this is very important at all. This seems like more of a architectural issue or problem depending on your site and is very unlikely to effect the SEO of your website. Here is a list of issues that could effect your website with regards to images.
- Images are downloading the content from multiple different websites thus increasing the number of resources to download.
- Images should be optimised for web and not just standard 72 dpi images. This will compress the images reducing the size of the resource been downloaded.
- Roll over images. Instead of using 2 images try using css sprites with just a single image. This also reduces the amount of resources been downloaded.
- Only use an image that is the right size. Using an image that is 2000x3000 in a space that is 200 x 300 is taking up probably greater then 10 x more space then is needed slowing your website down.
- Use alt tags with all of your images and it is advised to keep the image close to text and headers that best describe the image or that is relevant to the image.
- If possible use a CDN not just for images but for all static content. This will help to optimise your site not only for 1 country (which the above will only really do unless you have multiple servers serving the content) but for many other countries aswel.
Things that may help your sites performance.
- switch on persistant connections (may only be available if you have a dedicated server as this can increase server load)
the example below but this will only work if it has been activated in the httpd.conf file
## Keeps One Connection Open For HTTP ##
Header set Connection keep-alive
## END keep-alive ##
- enable caching in your htaccess file
## expire ##
ExpiresByType image/jpg "access 1 weeks"
ExpiresByType image/jpeg "access 1 weeks"
ExpiresByType image/gif "access 1 weeks"
ExpiresByType image/png "access 1 weeks"
ExpiresByType text/css "access 1 weeks"
ExpiresByType application/pdf "access 1 weeks"
ExpiresByType application/x-shockwave-flash "access 1 weeks"
ExpiresByType image/x-icon "access 1 weeks"
ExpiresDefault "access 1 weeks"
## End expire ##
Quickly explaining the above. The persistant connections will allow more then 1 http connection from your website to download the content. The number of connections depend on the setup of your httpd.conf file. Obveously the more connections the fast the content will download as instead of downloading a single item at a time it could be downloading 5 things at a time.
I have probably missed something but hope it helps.