"IMG_4821.jpg" as the filename and blank or auto-generated alt text is the default state for most product images. Descriptive, specific alt text (not keyword-stuffed) is one of the few remaining genuinely easy SEO wins left on most stores.
Oversized, uncompressed product images slow down the exact pages meant to convert, which hurts both Core Web Vitals and crawl efficiency. Modern formats (WebP, AVIF) at appropriate dimensions usually cut file size dramatically with no visible quality loss.
Product schema that correctly references the actual product images (not a placeholder or logo) helps Google associate the image with the right product data for rich results and image search both — a detail that's easy to get wrong during theme customization.