waifu2x (Image Upscaling and Noise Reduction)
A tool that raises the resolution of 2D images using a convolutional neural network. It handles photos as well as illustrations, and can reduce JPEG compression noise while upscaling. You can see for yourself how much jaggedness disappears when a small image is enlarged.
How to try it
Drag an image in or upload a file, then choose the style (art or photo), the noise-reduction level, and the scale (1.6x, 2x, or 4x) before running it. Uploads are limited to 5MB, with 3000x3000px for denoising and 1500x1500px for upscaling. The interface offers Korean, and a notice asking you to watch a short ad may appear on arrival.