Item listed successfully but not showing the picture/s for the item.

Question

Why pictures are not showing for items that listed via APIs when the Item's pictures are set to self-hosted URLs

Answer

There can be several reasons for the item picture/image issue. One of the reasons for the issue can be,  the self-hosted picture URLs is with 'HTTP' protocol.  

Self-hosted pictures must hosted on a site that is using the 'HTTPS' protocol. URLs using the 'HTTP' protocol will not be allowed. You need to use the 'HTTPS' protocol for the picture URLs.

Additional Resources

API Documentation:

 https://developer.ebay.com/devzone/xml/docs/reference/ebay/AddFixedPriceItem.html#Request.Item.PictureDetails.PictureURL

https://developer.ebay.com/api-docs/sell/inventory/resources/inventory_item/methods/createOrReplaceInventoryItem#request.product.imageUrls

Making your listings more secure: https://www.ebay.com/help/selling/listings/making-listings-secure?id=4363