Click the Cast icon above, then pick your device. The TV renders the slideshow in full quality, controlled from here.
② Mirror the tab
In Chrome's menu (⋮ top-right) choose Cast…, pick your device, then Sources ▾ → Cast tab. Mirrors this exact view. Works even without the button, quality is a little softer.
Casting needs Chrome or Edge on the same Wi-Fi as the device.
