http://www.twocows.com/preview/51102...q=jpeg+resizer Not the program I use, mine is old and the dotcom it came from is gone, but it looks about the same. Simple little program and twocows is a safe site. You want to compress your image enough that it reduces bandwidth use but not so much it becomes a blob. Any photo editing software will let you crop your image which will help a lot, I don't know how many huge images of small items in the middle of a large room I have seen on ebay.
Now I have a question, is that the only photo hosting site you can use here or will any web based image work with the insert image button?