# On-device AI versus server AI: what changes when you upload a selfie
When you use an AI tool on a photo, the model has to run somewhere. Where it runs decides who can see your picture, how fast the answer comes back, and what you can check yourself. This note compares the two designs in plain language.
Contents
# Two designs
Server AI. Your browser sends the photo to a computer run by the service. The model runs there and returns the answer. The service must handle your file, even if only briefly.
On-device AI. The page downloads a model once, then runs it in your own browser. The photo is read from your device and stays there. Browser technologies such as WebAssembly make this practical, and libraries like ONNX Runtime Web and MediaPipe exist for exactly this job.
# Side-by-side
| Question | Server AI | On-device AI |
|---|---|---|
| Does the photo leave your device? | Yes, by design | No |
| Can you verify that yourself? | Hard | Yes, with the offline test |
| First load | Fast | Slower, because a model downloads |
| After first load | Needs connection | Can work offline |
| Model size | Can be very large | Must be small enough for a browser |
# What you gain and what you give up
On-device models must be small, so they are often less flexible than the biggest server models. In return the privacy story is simple: there is nothing to delete later because nothing was collected.
Server models can be larger, but you are trusting a policy rather than checking a behavior. That is not wrong, but it is a different kind of trust.
# How to tell which one you are using
- Open the browser’s Network panel while you run the tool. An image-sized upload means a server.
- Try the tool in airplane mode after loading it. A result means on-device.
- Read the tool’s own explanation, then test it anyway.
# One example
Free Attractiveness Test takes the on-device approach. It scores one front-facing photo on a 60 to 99 scale using a model that runs in the browser, and the same photo always receives the same score. The site spells out how to run the checks above on its privacy page.
# Take-away
Neither design is automatically better for everything. For a personal photo, though, an approach you can verify in two minutes is worth preferring. For adults 18+ only.
Disclosure: written by the team behind Free Attractiveness Test.