Enlarge JPEG photos without the blocky artefacts
JPG is the most common photo format on the web, and also the most heavily compressed. When you upscale a JPG, the compression blocks and colour smearing grow along with the picture unless they are cleaned up first.
Why JPG files need special care when upscaled
JPEG compression divides the photo into 8×8 pixel blocks and throws away fine detail the eye is unlikely to notice at the original size. Enlarge that JPG two or four times and those block boundaries and ringing around edges become obvious.
Turn on noise reduction first
The median denoise option smooths compression speckle before sharpening, so the unsharp mask boosts real edges rather than JPEG noise.
Choose Lanczos or Deep Enhance
Lanczos keeps edges crisp for clean JPGs. Deep Enhance, based on Real-ESRGAN, was trained on compressed photos and handles heavily degraded JPG files better.
Export options for an upscaled JPG
You can download the result as JPG with a quality slider, or as PNG if you plan to edit it further and want to avoid a second round of compression. Either way the file is created on your device.