Générateur d'image de mauvaise qualité

Your image is decoded in the browser with EXIF rotation applied, so photos taken on a phone stay upright. It is then drawn onto a hidden canvas at a fraction of its original size, set by the resolution scale slider. Detail that does not survive that squash is gone for good, which is where most of the degradation comes from.

If grain is turned up, random noise is mixed into the pixels while the image is still small, so the noise ends up the same size as the pixel blocks. The small canvas is then drawn back up to the output size. Blocky resampling turns off pixel smoothing so every shrunken pixel becomes a hard square; smooth resampling blends them into a blur instead. The deep fry slider applies a saturation and contrast filter during that final draw.

The result is encoded with the quality you picked, or with a quality found by binary search if you set a target file size. Extra recompress passes decode and re-save the file repeatedly to compound the artefacts, the same generation loss that degrades an image reposted over and over. The preview renders at a reduced resolution to keep slider dragging smooth, and the full-resolution version is built when you download.