Online shoppers rely on product images to gain information about products. Helpful product images allow a detailed mental imagery of the product and its use. Product images with a fitting contextual background, as opposed to a plain white background, increase such mental imagery and in turn product liking and purchase intent. This effect, however, is preceded by imagery fluency—the ease with which mental images come to mind in the first place. As a result, effective product images need to facilitate fluent perceptions, while also evoking fitting mental imagery. Two experimental studies confirm this pathway which links research on mental imagery with research on imagery fluency. Moreover, the experiments show that this effect of contextual backgrounds works for fitting but not for non-fitting backgrounds, better for ambiguous than unambiguous products, and for experience products, but not for search products. Online retailers could leverage contextual backgrounds in product images to enhance consumers’ evaluations of their merchandise as long as the beneficial effects via mental imagery outweigh the added photography costs. © 2018 Elsevier Ltd