Missing alt and empty alt are different findings. Informative images need text that communicates their purpose in context. Decorative images may correctly use an empty alt attribute. Automated inventories identify candidates for review; they cannot reliably decide the role of every image.
Create an inventory before rewriting
Run the image SEO checker on a representative page. It lists image sources, alt values, declared dimensions and loading attributes from the fetched HTML. Start with the images that have no alt attribute at all. Then review empty values in the page itself. Do not automatically replace every empty alt with a filename: doing so can add useless noise for people who use assistive technology.
Describe the image's purpose
For an informative image, ask what a visitor would miss if the image did not load. An image showing a chart's conclusion needs a different description from a product photograph or a linked logo. Context matters: surrounding text may already explain part of the information, while an image that acts as a control needs a clear action or destination. Write for understanding rather than repeating a list of search keywords.
Recognize decoration and duplication
Background flourishes, separators and purely decorative illustrations often need no spoken description. An empty alt on an img can make that intention explicit. An image immediately beside text that communicates the same information may need different handling from a standalone informative image. Review the rendered page and the interactive role before choosing. The inventory's Verify state for empty alt is deliberate: it asks for judgment rather than declaring an error.
Reserve layout space intentionally
The checker flags image elements without both width and height attributes. That is evidence worth reviewing, but CSS can reserve space with an aspect ratio or a fixed container. Inspect the mobile layout during image loading to see whether content jumps. Keep the intended aspect ratio consistent with the actual image. The tool does not measure layout shift and cannot infer every responsive CSS rule from the raw image element.
Review loading in the actual layout
Lazy loading can help images well below the initial viewport. An important hero image may need different treatment. The checker reports the declared loading value without turning it into a universal pass or fail. Test the page at realistic connection speeds and screen sizes. Also review srcset and image formats where appropriate; the free inventory does not download files or calculate their sizes, so it cannot tell you that your images are optimized.
Use a sample across templates
Inspect a homepage, an article, a product page and any gallery template you use. Fix common missing attributes in the shared component when the same issue appears repeatedly. Then retest one example from each template. A clean inventory is useful evidence, but it is not a complete accessibility assessment. Keyboard behavior, contrast, accessible names, relationships and user testing require a broader review of the rendered experience.
A practical action checklist
- Inventory the image elements on representative pages.
- Review missing and empty alt separately.
- Write context-specific descriptions for informative images.
- Confirm that loading images do not move important controls.
- Fix shared components and test the rendered experience.
NewSiteCheck workflow and examples. Review important production decisions against the applicable official documentation.