Hi Andy,
Thanks for contributing to our forum.
I reviewed the most recent examples of this behavior you provided in the support case you filed on this subject and confirmed that we sent the images in question to eBay as 800 x 800 px and 1000 x 1000 px successfully, so the resizing in question was done automatically by eBay.
The only option I am aware of that would allow you to increase the size of your gallery images is to use the optional “Supersize” option, which generally entails an additional fee as described in the “Listing Upgrades” section on the following eBay UK Help page:
http://pages.ebay.co.uk/help/sell/fees.htmlOn that note, I did some testing and found that (at least in my case), the “Supersize” option is not being submitted to eBay correctly when selected from within the “Marketing Tools” section of the Auctiva lister page and I have asked our technical team to look into that further.
I am not entirely sure I understand the issue, but we will follow up with you again through your open support case and can continue to communicate through there if we are not currently on the same page.
-Mike