Stability AI’s New Upscaler Can Quadruple the Resolution of an Image

Stable Diffusion

Stability.AI, the company behind Stable Diffusion, has announced a new artificial intelligence-powered upscaler that is capable of quadrupling the resolution of an image.

The artificial intelligence (AI) upscaler is being released as an API and Stability.AI claims it can increase the size of any image up to four times its original resolution without compromising sharpness.

“The Image Upscaling API is the latest addition to Stability.AI’s existing set of image generation and editing APIs, like the popular text-to-image, image-to-image and inpainting APIs. Upscaling adds to those popular tools by expanding small images into larger ones while maintaining — or even improving — their level of detail,” the company says.

“Since the emergence of digital imagery, it has been nearly impossible to expand small images into larger ones without compromising the quality of the image. Now users can pass a small image into the API and get back one with more than double the level of detail.”

Stable Diffusion

The concept is similar to other upscalers like Adobe Super Resolution or Topaz Gigapixel and has two ways it operates, both of which are open source.

The first is designed for speed and is called Real-ESRGAN. says it can double the resolution of a typical 512×512 pixel image in half a second. The second is significantly slower, but more powerful. It uses the Stable Diffusion x4 upscaler model and can quadruple the resolution of an image in somewhere between 20 and 40 seconds. The company says that it provides more detailed results and a “richer texture” in exchange for that significantly longer computation time.

“Both models can be used to upscale any images, whether they were generated using the Stability API or not. A key advantage of the latent Stable Diffusion 4x Upscaler is its advanced diffusion process that increases the perceived level of detail while upscaling the input image,” Stability.AI says.

Stable Diffusion

“The introduction of these models aligns with our vision to continuously enrich the Image Upscaling API with state-of-the-art models as they become available.”

Stability.AI has published full documentation for its upscaler APIs on its website in addition to sharing Real-ESRGAN on Github and the x4 upscaler on Hugging Face. The company doesn’t specifically note how or if its API will work with actual photos.

Those who already use Stability for Photoshop or Stability for Blender will see the new upscaling features added into the latest versions of those immediately.

Image credits: Stability.AI