You want the whole article as one image, not a series of viewport screenshots.
Full-page capture scrolls the page and stitches the frames into a single tall image. Fixed and sticky elements such as headers would normally repeat in every frame; Omni hides them after the first frame and restores them afterwards. Capture stops at 60 frames, roughly 60 viewport heights, and tells you when it truncates.
Trigger full-page capture from the toolbar, the palette, or its shortcut. If you need the capture permanently, download it from the editor; the cloud library cleans up captures past their retention window nightly. For AI reading, remember images are downscaled to a 1,568 pixel long edge before being sent, so prefer region captures of sections as model input.