Hi sobluex,
Welcome to Auctiva! Just to follow up on Danno's previous past, the button on the description editor toolbar that can be used to insert images directly into the description editor is located near the bottom-right of the editor toolbar and has an icon of a mountain and sun on it.
Any additional questions or concerns? Please feel free to contact our customer support team using the appropriate link on our help page: http://www.auctiva.com/free-auction-software-help/help.aspx
-Mike