A product image is the first and often the only thing a customer evaluates before clicking away or adding to cart. We've seen conversion rates double just by replacing product photos. Not an exaggeration.
Right size
WooCommerce generates three image sizes: thumbnail, product image, and gallery image. Upload originals at least 1200 pixels on the widest side. WooCommerce creates intermediate sizes automatically. Under WooCommerce → Settings → Products → Display you can set the dimensions. Consistent sizing gives a clean catalog page.
White background
If you sell physical products: white or light gray background. No shadows, no distracting elements. Amazon requires it for a reason. It makes the product stand out, images stay consistent, and customers can compare without visual noise.
Lifestyle images work as supplements in the gallery. But the main image should be clean.
File format and compression
WebP as primary format. JPEG as fallback. PNG only when transparent background is needed. Compress with ShortPixel or TinyPNG before upload, or let a plugin handle it automatically.
Alt texts
Every product image should have an alt text describing the product and variant. "Blue cotton t-shirt, size M, front view" is better than "product-123". It helps SEO and accessibility at the same time.
Gallery
At least three images per product. Front, back, detail. More images reduce returns because the customer knows what they're getting. It's an investment that pays for itself.