eBay user shipscript wrote the free tool and has improved it. She has just posted in the eBay Photos & HTML forum about the new and improved version of the tool.
Please go here to read all about it.
http://forums.ebay.com/db2/topic/Photos-Html/Check-Your-Image/5100155946
It now helps you go in and edit the listings that are not a the minimum of 500 pixels and has a tool to enlarge them to 500 pixels to replace the smaller photos.
An all in one free tool to help you get your listings with undersized photos fixed in time for July 1st.