Fairly certain it’s always been the case.

one of the reasons is it’s actually googles rules as well for Google Shopping, so at least historically, when eBay used to use fees to bid for placement in Google Shopping the images you provided needed to meet Googles requirements.

that being said..

-Google now allows you to create images with AI backgrounds in Google Merchant Center (though their white background policy still applies in the written policy)

- eBay did a presentation on this matter the other month, outlined the white background policy but then on the next slide proceeded to use an example of a ‘good’ listing that was surrounded by upsell graphics.

so who knows?