Product images are common offenders
Stores often have hundreds or thousands of product images, uploaded by different people in different sizes — and almost always without alt text. The list filters find them, the bulk actions fix them.
AI with product context (Pro)
With "Use WooCommerce context" enabled, the product name is included when the AI generates metadata for a product image. The result is noticeably more accurate: "Black Pahlén Calidi PP pool heat pump" instead of "black machine on white background". Combined with bulk AI, a whole catalogue can get correct alt text in minutes.
Zoom images and scaling
The WooCommerce zoom feature needs images of at least ~1500–2000 px. The default maximum of 2560 px keeps zoom intact — avoid scaling product images below ~1500 px if you use zoom.