This error occurs when, using deferred image loading functionality, it is not possible to identify the maximum width of an uploaded image for a product with ID xxxx ([xxxx] Cannot determine image max width).

First, ensure that you actually need this functionality: it should only be used if there are issues on eBay with classic uploading and image visibility; otherwise, images are uploaded normally via links during classic synchronization.

If you do need this functionality and encounter the error, check from the back office that the images for the product in question are visible and not corrupted. In such a case, make sure to replace them and relaunch the loading procedure to eBay once the problem is resolved (since it is incremental, it will attempt to reload only the missing images).

Also, consider that the procedure is capable of supporting images in JPG and PNG formats. If you are using third-party modules or have enabled support for WEBP / AVIF images, deferred loading is not possible.