HTML frames (render contract,

Freeze frames of an animation under the render contract: the page defines window.renderAt(t). The tool renders the self-contained HTML document in headless Chromium with all network access refused, calls renderAt for each requested time in seconds and returns a PNG still per time (base64) plus one contact-sheet PNG of every still in a grid. For previews and frame checks of canvas, SVG or CSS animations an agent wrote itself (motion design, motion graphics, generative art).