We're in the middle of looking at the benefits of using Magento rather than Actinic/Sellerdeck, but one of the main problems we cannot find a way around so far is that we would need to keep our image paths as our images are referenced elsewhere, such as eBay. Under Sellerdeck all our image URLs are under one location, so for example the image "bob.jpg" will always be under "http://[site URL]/acatalog/bob.jpg".
It wouldn't be a problem for new images to have a different structure, but we need all our old products images to still be available under these URLs, there's just too many to change manually, does Magento have any support for this?