We've been housekeeping on the servers in the last few days. We've noticed some of our clients using very large image files on their websites - some are as large as 5Mb!!
It's only a problem if you include these images on your pages - you're forcing your website visitors to download them - this will take a long long time even with a reasonable connection speed. Many people won't wait for the page to load.
Image files used in a page should really be no bigger than 50kb. Read our knowledgebase article for more information on how to use images on your website.