I'd recommend the HELP Tutorials that can explain alot to new Auctiva members.
http://www.auctiva.com/help/tutorials.aspx
You can upload images to Auctiva from either the one-page lister, or from the Images tab by selecting Upload Images and you get a page with 3 methods: Drag-and-Drop, Java Uploader, and Basic HTML Uploader. The limitations for each are listed to the right for each method.
Danno