Why it matters
Alt such as "image", "IMG_2231.jpg" or a pasted paragraph adds no meaning for search or assistive tech.
How to fix it
Describe what the image shows in context, in about 5–125 characters.
References
More seo rules
void seo reports 60 rules in this category. What search engines need from the raw response: status codes, titles and descriptions in <head>, self-referencing canonicals, one h1, crawlable links, Open Graph, icons, robots.txt and a sitemap with real dates.
h1-countPage doesn't have exactly one visible <h1> in the server HTMLh1-title-mismatch<h1> and <title> share little wordingheading-skipHeading levels skip (h2 → h4) or headings are emptyimg-alt-missing<img> without an alt attributelinks-not-crawlableNavigation uses elements crawlers can't followlink-textLinks with generic or empty textbroken-linksInternal links return 4xx/5xx (or go through redirects)trailing-slashBoth trailing-slash and non-slash URLs serve 200