Turn a photo or AI-generated image into a two-tone (duotone) graphic and save it as a PNG, entirely in your browser. Whether you want a consistent, stylish look across social thumbnails and banners, a poster- or album-cover feel, or that eye-catching Spotify-style campaign tone, you can do it in one tap without opening a heavy image editor. The effect is simple: each pixel's brightness (luminance) is measured, and dark areas are mapped to a shadow colour while bright areas take a highlight colour, with smooth blending in between. You can pick the two colours freely, hit Swap to flip them, or tap a preset (blue × gold, purple × pink, and more) to apply a pair instantly. The Intensity slider blends between the original and the full duotone: 100 fully recolours the image, 0 leaves it untouched, and values in between nudge the colours subtly. The preview is scaled to fit your screen (up to 2048px on the long side), but the saved PNG is exported at the original pixel size. You can load images by dropping, clicking to choose, or pasting from the clipboard. All processing happens in your browser — the image is never sent to any server or API, so it's safe to use even where uploading files is not allowed.