Image SEO tips that still matter

Google says using standard HTML image elements helps crawlers find and process images. It also states that Google does not index CSS images. If a key photo is set as a CSS background, Google Images will not pick it up.

Google calls alt text the most important attribute for providing metadata about an image. It also improves accessibility for people using screen readers or slow connections.

Google uses alt text along with computer vision and the page content to understand an image, and alt text works as anchor text if the image is a link. Google's advice: write useful, information-rich alt text that fits the page, and avoid filling alt attributes with keywords. It warns that keyword stuffing creates a negative experience and may cause a site to be seen as spam.

A quick test: would the alt text help someone who cannot see the image? "Technician replacing an AC compressor on a rooftop unit" passes. "AC repair HVAC Irvine best AC" does not.

Google says filenames give very light clues about an image's subject. Its example: my-new-black-kitten.jpg is better than IMG00023.JPG. Light clues still count, and renaming before upload takes seconds.

Google extracts information about the image from the page, including captions and image titles. Place images near the text they illustrate, on pages that match the image's subject. Google's SEO Starter Guide gives the same advice: add high-quality images near relevant text.

Google lists supported formats: BMP, GIF, JPEG, PNG, WebP, SVG and AVIF. It also suggests making the filename's extension match the file type.

An image sitemap helps Google discover images it might otherwise miss, and Google notes it can list images hosted on other domains, such as a content delivery network.

Google recommends responsive images, using srcset or the picture element so each device gets a suitable size. It also notes that high-quality photos appeal to users more than blurry ones. Our read: compress for speed, but not until the photo looks cheap.

1. Open a key page and check that each important image has alt text.
2. Look at the filenames. Rename any camera defaults before the next upload.
3. Check that hero images are HTML images, not CSS backgrounds.
4. Run the page through PageSpeed Insights and look for oversized images.
5. Confirm your sitemap, or an image sitemap, includes your important images.

Does alt text help rankings? Google uses it to understand images, and it is the most important image metadata by Google's account. Write it for people.

Should every image have alt text? Our read: images that carry meaning need a description, while purely decorative images can use empty alt text, a common accessibility practice.

Which format is best? Any supported format works. WebP and AVIF usually give smaller files at the same quality.

Image SEO is mostly housekeeping: real HTML images, honest alt text, clear filenames and fast, sharp files. Build it into your upload routine once and it pays on every page.