AVIF is the future of web images. It’s a next-generation format that offers significantly better compression than JPEG or WebP — smaller file sizes, faster load times, and no visible quality loss. WordPress has supported AVIF since version 6.5, and an increasing number of themes and hosting providers are generating AVIF versions of uploaded images automatically.
But there’s a catch. Most alt text tools don’t support AVIF.
Why AVIF support matters for alt text
Alt text tools that process images via URL need to be able to read the image file. AVIF uses a different encoding structure to JPEG or PNG, and older image processing libraries — including many used by WordPress plugins — can’t decode them. The result is that AVIF images either get skipped entirely, generate an error, or fall back to a generic placeholder.
AltText.ai charges double credits for AVIF images and restricts the feature to paid plans only. This makes AVIF images more expensive to process — which creates a perverse incentive to avoid a format that’s genuinely better for your site’s performance.
ALTification supports AVIF at no extra cost, at the same credit rate as any other format. If your theme or hosting generates AVIF images, they’ll be processed correctly and you won’t be penalised for using a modern image format.
The accessibility angle
AVIF adoption is accelerating. As more WordPress sites move to AVIF by default — either through theme settings or hosting-level optimisation — the gap between sites with proper alt text and those without will grow. A site that generates AVIF images automatically but has no alt text generation tool that supports them is accumulating an accessibility debt with every image upload.
Getting AVIF alt text right now, before it becomes the universal default, means you’re not playing catch-up later.