Is there a way to check if my current listings comply with eBay’s image-size policy?

eBay  recently updated their Picture Quality Requirements – now requiring every picture to measure at least 500px on its longest side. If you have listed products using smaller images in the past, you might not be able to revise them in WP-Lister until you have updated your product images in WooCommerce.

To check your currently active listings whether they match the latest requirements, there is an excellent online tool to do so at:
http://www.isdntek.com/ebaytools/ListingPhotoSizes.htm