Koutuxia removes the background from a photo and hands you a transparent PNG. The free path runs BiRefNet-lite in the browser: a 78 MB fp16 model downloaded once from a CDN and cached, then executed on WASM SIMD, dropping to a 39 MB model at a smaller input size on weaker hardware. An opt-in maximum quality mode swaps in a 191 MB Swin-Large backbone. You can touch up the cutout by hand with erase, restore and smart brushes, with undo. A paid cloud path gives finer edges, higher resolution and batch jobs.

Around the cutout there is a set of image tools. One-click background swap to red, blue or white. A magic eraser: brush over a person or object and AI fills in the scene behind it. Unblur and restore for shaky, low-res or over-compressed photos, with a non-generative deconvolution mode that runs in the browser and an AI mode that rebuilds detail and restores faces separately. Repair text in a photo. Resize, compress and convert between JPG, PNG and WEBP without uploading. And an Image Studio that chains clean-up, cutout, background replacement, resize and export in one resumable workflow.

The browser-side tools are free and need no signup; the AI modes draw on a Pro cloud quota. Pro is a one-time purchase or a subscription, paid with WeChat Pay, Alipay, card or PayPal. The site works from mainland China without a proxy, and there are iOS and HarmonyOS apps.