If you need sound advice on how to improve your photos, see camerajim's Photo Tips at...
http://sigma-2.com/tips/camerajimstips.htm
http:ttp://www.bulls2.com/help/photgraphing-clothing.html
And here are some great tutorials by nktower on lighting, photographing small objects, editing (including cropping, resizing, and compressing) your pictures using irfanview, and presentation of your pictures on eBay. Even though the author used irfanview (a free download), these tutorials are generic enough to help regardless of the photo editing program you use.
http://www.deadzoom.com/member/nktower/tutorials.html
Taking Pictures on a Budget (from Bob's Tips)
http://www.bulls2.com/indexb/picturesonabudget.html
To see how your web-hosted picture fits on screens with different resolution settings (from Concho's tools)
http://auctionrepair.com/imgsize.html
A quick way to resize your picture online
http://www.imagetweak.net/