OverlayImage.app Keeps Image Compositing Small and Local

Field notes

The editor starts with a base image and permits up to five independently selectable overlay layers, which can be moved, resized from their corners, rotated, mirrored, and reordered. Each layer has visual adjustments including opacity, brightness, contrast, saturation, blur, and blend mode; the page specifically describes twelve modes. Export offers PNG, JPEG, and WebP, with PNG positioned for transparency and WebP for smaller web-ready files. The site states that processing remains local to the browser.