When uploading an image to blob storage for a product, it should copy to a latest blob as well as copying to a versioned blob.
Eg image uploaded to products/raw/prodref/3/blob should also upload to products/raw/prodref/latest.
This way you don't need to lookup in the database for the version of the image to be displayed, nor have to specify it for streamProductImage.aspx.
Instead, we should throw some sort of warning or exception in the streamproductimage code whenever a request is made with no version number, or no height, or no width, or no colour.