You can also adjust the cover image on desktop in terms of aspect ratio. Adjust it there can make the thumbnail look different. It's a little botton to the bottom left that shows up sort of like two angle brackets. It's easy to miss tbh, but go through the flow of posting again and on every step look for it, it's in one of the early stages.
![BRASIL vs. URUGUAY [1-1] | RESUMEN | ELIMINATORIAS SUDAMERICANAS | FECHA 12](http://i.ytimg.com/vi/-hWBAuxF1eY/mqdefault.jpg)
You can also adjust the cover image on desktop in terms of aspect ratio. Adjust it there can make the thumbnail look different. It's a little botton to the bottom left that shows up sort of like two angle brackets. It's easy to miss tbh, but go through the flow of posting again and on every step look for it, it's in one of the early stages.