Upscayl

Upscayl is a free app for Windows, Mac and Linux that enlarges low-resolution images using AI models. You drag in a picture, choose a model that suits the type of image, and save a version at two, four or more times the size. Because it runs entirely on your own computer, your images are never uploaded, and there are no limits or subscriptions. It supports batch processing and lets you add custom models. Upscayl is open source and free to use. It is a great pick if you want quality upscaling without paying or sharing your files.