You can do this by creating your own template and using the tag:
[IMAGE1_ORG] - the entire HTML <img> tag for your original image, no resizing, borders, click-to-superize link, etc.
We wont be adding an option to not click to supersize. Full size images are too large and slow. Too many people would use it without knowing the ramifications. The current use of 400x300 images with click to supersize is the perfect compromise. Large enough to see needed detail, fast to load, and the serious buyer can click to size a full size image. Every company including eBay does it this way.
We still provide the template tags to do whatever you want if you create your own template. It's even easy to start with one of our templates and make the changes to it you want.