To find out the size of banners on Elite sites follow below:
Right click on the image and select Inspect - you will see a page of coding:
The image you have right clicked on is highlighted in blue in the script.
You need to update the Dimensions: Responsive area to 1920 (there is no need to choose a device from the dropdown list, just update the first number box)
If you don't see this at the top of your page - click on the Toggle Device Toolbar icon:
Simply overwrite any numbers in the first box of the Dimensions: Responsive area and click away.
Now place your cursor over the blue highlighted area and it will show you the size of the selected area/image:
Logically round up or down any decimal pointed numbers - for example the one above would be 1890 x 708 but would also work as 709.