The thumbnail image that shows on our site is the first product image sent along with the product details from your store.
We only sync images that are at a product level not at a variant level so please ensure the images are set up against the product
If no images are available or the image url was broken, we won't be able to display anything.
If you have added or updated the images, these should show on our side within an hour but you can re-sync your account before this.
To re-sync your account, please go to your sales channel and select configure
Next go to the sales channel settings
Finally, press the update now button
if you have done all of the above and the thumbnails still haven't appeared, please send screenshots of the products missing these to the support team so we can start an investigation help resolve this for you as soon as possible.