This is most likely due to one of the following things:
- The TV was off when the Raspberry Pi booted up, thus preventing it from detecting the resolution of the monitor
- The resolution of the TV is unsupported by the Raspberry Pi (Raspberry Pis prior to Raspberry Pi 4 Model B only supports up to 1080). It’s hard to see in the photo but it looks like an ultra-wide monitor.
We generally recommend using 1080 content (i.e. 1920x1080) for best experience.