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Image filenames
You can now control the filename with which any image is published in a website or web document, which can help SEO and your position in image search. Select the object and open Utilities > Web Properties > Image tab. In the Image section of the dialog you can set the preferred filename to be used. If the filename is not unique within the current website/document, Designer will append a number to the name to make it unique.
I haven't had enough time to check yet but I believe this will also eradicate the BIG issue with using the previous 'filename=image" naming convention that led to issues between variant image quality.