By default, rich image fields on WCM pages only allows author to pick images that already exist in SharePoint. With "SharePoint 2010 Image Field Upload", you can also upload directly an image from your computer in rich image fields.
Image Field Upload is now provided as a sandbox solution that will register both jQuery and Image Field Upload scripts, so it can be installed in few clicks by any site collection administrator.
page for the step by step installation guide.
Image Field Upload in action
Image Field Upload adds a link into each image field control so users can upload images directly from their computers, as shows the screenshot below.