Upscale an image with AI

What upscaling can and cannot do

Plain resizing, such as Image › Image size…, spreads the pixels a picture already has over a larger area, so edges go soft and textures turn to mush. The upscaler is an AI model trained on many pairs of small and large pictures: it draws crisp edges and plausible texture where resizing would blur.

It shines on small web pictures, old phone and camera photos, screenshots and logos that must be bigger than the file you have. It cannot recover detail that was never captured. Tiny faces, distant text and number plates come out as the model's best guess, which can look sharp and still be wrong, so never rely on an upscaled picture as evidence of what was really there.

2× or 4×, and how big it can get

2× doubles the width and the height, four times the pixels. 4× makes them four times larger, sixteen times the pixels. Pick 2× when the picture is already decent and needs a little more room; 4× for small pictures.

The result has to fit in your graphics card's largest picture, which is 16,384 pixels a side on most PCs. A 3000-pixel photo goes to 12,000 at 4×, but a 5000-pixel one cannot: Octoolo says so, and 2× or a crop first is the way through.

For print, divide the pixels by 300 for inches at sharp print quality: a 1200-pixel picture prints at 4 inches, and the same picture at 4× at 16 inches. Large pictures make large files, so export photos as JPG or WebP at a quality of 85 to 90 unless you need PNG.

Layers, text and exact sizes

Upscale works on every photo layer in the picture, one after the other, and the progress counts them. Text, shapes and color fills are not pictures but drawings, so they simply grow with the canvas and stay perfectly sharp; masks grow along with their layers.

Need a size between the two, such as 3× or exactly 3000 pixels wide? Upscale 4×, then choose Image › Image size… and type the size you want. Making a sharp picture smaller keeps it sharp, so this gives a better result than enlarging by plain resizing.

The AI part is downloaded once and checked, then runs on your PC with no internet. AI › AI parts on this computer… shows it.

Before and after upscaling

• Crop first. Upscaling only the part you need is quicker and stays within the size limit. See crop image.
• Clean up after. A JPG's compression blocks can be enlarged along with the picture; a touch of Filter › Reduce Noise afterwards smooths what is left.
• Logos may be better traced. A logo that has to be huge, for a banner or a sign, is better turned into shapes that are sharp at any size: see PNG to SVG.
• Keep the original. Export the large copy under a new name; Octoolo never changes the file you opened.