Shein has lost a copyright case against online shopping rival Temu in the UK, in a decision that could affect how online marketplaces are held responsible for material posted by independent sellers. The case was heard in London and centered on thousands of product photographs that Shein said had been copied and used on Temu’s website without permission. Shein had accused Temu of copying its images on a large scale and argued that the rival company benefited from photographs created for Shein’s own clothing products. The dispute is part of a much larger fight between the two fast-growing companies, which compete for shoppers looking for inexpensive clothing, household items, accessories and other products. Thelawsuitfocused on whether Temu could be held responsible for images that appeared on its platform.