I find it very unlikely that the price of the products is provided by thirdparty data provider, and think the actual price is not covered by them despite them suggesting it might be.
Copyrights are inadvertent and sometimes unintuitive. If the images are created by the product manufacturers, then they hold the copyrights. If the supermarkets edit the images, then they hold copyrights to these edits.
Likewise, if trolley edits the images (undoing the supermarket edits, like cropping around some text) then trolley together with the manufacturer holds the copyright for this new image, not the supermarket.
It doesn't matter where it was scraped from or who was hosting the image, just as it doesn't matter which camera was used.
Really, they don't need product data beyond the name. They could drop pictures and detailed data and build their own database by crowdsourcing pictures and data from their users.