I have a server, a website of mine, hosted by
www.bluehost.com .. I pay about $92 per year to host my company's website.. I get e-mail and all that stuff..
I upload pictures via ftp to
www.mysite.com/ETC/
Then on eBay I edit HTML code and insert a picture like so
<img src="http://www.myserver.com/ETC/pic01.jpg"></img>
For eBay description pic or gallery pic I just upload it to eBay using their tool, from my desktop.
That's cheap for me because I already host a website.. For you, and if you don't want a website, you can look for free photo album site.
http://www.google.com/search?hl=en&q=free+photo+album
Check them all out, you get image url and you can create code like above. Provided that the site allows you to do it on remote sites such as eBay.