Make images useful, accessible and fast without turning alt text into a keyword field.
Choose the right asset before optimizing it
The first image optimization decision is whether the image is necessary. Decorative media has a performance cost, while a useful diagram, screenshot, product photo, or illustration can add information that text alone cannot communicate as efficiently.
Use raster formats for photographic or complex imagery and vector formats for logos and simple illustrations when appropriate. Modern formats can reduce transfer size, but compatibility and your delivery pipeline should guide the final choice.
Serve the dimensions the layout needs
Uploading a 4000-pixel image into a 600-pixel content column wastes bandwidth. Generate responsive variants and let the browser select an appropriate source for the viewport and device density. WordPress can generate intermediate sizes, but the theme must request them correctly.
Declare width and height or aspect ratio so the browser can reserve space before the image loads. This reduces layout shift and improves visual stability.
Write alt text for the image's purpose
Alt text should communicate the meaningful information a user would miss if the image could not be seen. A screenshot may need to describe the interface state. A chart may need a short summary plus nearby text containing the full data. A decorative flourish may need an empty alt attribute.
Do not fill alt text with SEO phrases. Keyword-stuffed descriptions are less useful to assistive technology and do not make a low-value image more relevant. Write for accessibility first.
Load below-the-fold images lazily
Native lazy loading can reduce initial network work for images that start outside the viewport. However, do not lazy-load the primary above-the-fold image if it is likely to become the LCP element. Delaying discovery of the main visual can directly hurt perceived speed.
Preload only assets that are genuinely critical. Excessive preloading competes for bandwidth and can make the page slower. Use performance traces to confirm which resource should be prioritized.
Use descriptive file and surrounding context
A readable filename can make asset management easier, and the text around an image helps search systems understand what it represents. Captions are useful when they add context, not when they simply repeat the heading.
For original diagrams or data visualizations, provide enough nearby explanation that the information remains accessible and indexable. Important facts should not exist only as pixels inside an image.
Audit media as part of the template
Image SEO is inseparable from performance and UX. Check broken images, oversized files, missing dimensions, inappropriate lazy loading, empty or redundant alt text, and mobile cropping across representative templates.
A media pipeline that automatically produces sensible sizes, formats, and metadata is more reliable than manually fixing every image after publication.
Practical implementation checklist
- Choose images that add information or meaningful visual value.
- Serve responsive dimensions instead of oversized originals.
- Write alt text for accessibility and purpose.
- Reserve width and height to prevent layout shifts.
- Lazy-load below-the-fold images, not likely LCP media.
- Audit templates for broken, heavy or redundant images.
Related reading
Use AEO & GEO Insights to inspect crawlability, answer structure, entity signals, evidence and semantic readiness on a public URL.
