An object remover is a selective image-editing tool: you mark an unwanted subject, and the covered area is reconstructed to fit the visible scene around it. The mask is the control boundary. It tells the editor where change is allowed, which is materially different from sending the whole image with a vague text request.
Img ai converts the uploaded source into a same-dimension working PNG, draws a white edit mask beneath the overlay you see, and keeps protected mask pixels black. Your source URL, mask URL, brush setting, selected bounds, and task identity are saved with the private task record so retries do not create a second charge.
Reconstruction is still generative, not forensic recovery. It creates a plausible continuation of color, light, texture, edges, and perspective; it cannot reveal the original pixels hidden behind an object. Treat every output as an editable result that needs human inspection.