Wed Apr 08 2026 08:00:00 GMT+0800 (Taiwan Standard Time)

Remove a background online without uploading the photo

An online background remover can still keep the file on your device. Here is what LocalBG sends over the network, and what it never sends.

“Online” and “uploaded” are not the same thing. LocalBG is online in the sense that you open a URL. It is not an upload tool. The page has no form action, no fetch of the image to an API, and no analytics call that could smuggle pixels along.

When you press Remove background, a Web Worker does three things that stay on the machine: it resizes a copy of the pixels to 512×512, runs the ONNX session, and paints the matte back onto the original resolution you chose. The worker can also download the model if this browser has not cached it yet. That request is a GET for model_fp16.onnx. It has no image body. Static files for the page itself — JavaScript, CSS, the ONNX Runtime .wasm — are GET requests too.

How to check

You do not have to take the badge at its word. Open the browser’s network panel, filter by method, and run one image. You should see no POST or PUT. The photo never appears as a request payload. The privacy note on the tool says the same thing in the interface: your files never leave your device. The longer version is on the privacy page.

Why this is harder than it looks

A background model is large. Hosting a 94 MB file on Cloudflare Pages would break the 25 MB per-file limit, so the weights stay on the Hugging Face CDN and are cached locally after the first fetch. The WebGPU build of ONNX Runtime is about 29 MB, so that binary is loaded from jsDelivr at a pinned version instead of being copied into the site. Both of those are asset downloads. The photo is not in either one.

If a site asks you to “upload to remove the background,” it is doing the ordinary thing: sending the file. LocalBG is the version that skips that step.