Other than the use of plugins, there are other best practices that can be used to speed up the blog.
scale it down to the exact pixel size and also to 72dpi. This will make it load faster
2- Other Plugins
Try to see if there are other plugins thats causing it to load slowly. For me, the 'sharethis' plugin caused my website to load really slowly and when I deactivated it, it loaded much faster! So, that might be the cause.
It's good to clean up and streamline your CSS to make increase loading time. I read this somewhere on the website A List Apart.
4- Check your WordPress loops
The more php processing your theme requires, the longer it might take for your page to load. So, again, its good to surf around and find tips to streamline your code.
Hope this helps in some way:)