About the Image SEO & Alt Tag Checker
Images enhance user engagement and visual storytelling, but unoptimized images can drag down page speed, harm accessibility, and cause layout shifts. Optimizing image metadata — particularly alternative text (alt text), explicit dimensions, and modern formats — is crucial for both SEO and user experience.
The alt attribute serves two primary purposes: it allows screen readers to describe images to visually impaired visitors, and it provides search engine crawlers with contextual information about image contents, enabling ranking in Google Images.
This Image SEO Checker extracts all <img> elements from pasted HTML, flagging missing alt attributes, purely empty alt text, non-descriptive generic filenames (e.g., 'image.png'), missing width/height dimensions (which trigger Cumulative Layout Shift - CLS), and unoptimized image formats.
A common mistake is keyword stuffing within alt attributes (e.g. alt='best seo tools free seo tools download seo software'), which violates Google guidelines and degrades the screen reader experience. Another mistake is omitting explicit width and height attributes on responsive images, causing visual jumps as images load.
Tip: Write descriptive alt text that explains what the image actually depicts within 5 to 15 words, include relevant context naturally, and always declare width and height attributes.