Since the demo images aren't imported in the Media library during the quick import, in case you need to find out what is the size of a particular image in our demo website, you can do the following:
The easiest way is to hover over the image and click with "Right-mouse-button" on the image. Then you'll see the standard options:
Click on "Open Image in New Tab"
Look at the image URL and you'll find the right image's size.
Click on "Save Image As...", save the image on your computer and check the its size the standard way: hover over the image and click with "Right-mouse-button" on the image. Then select "Get info" or "View image properties"
Sometimes this way isn't possible directly and you have to prior reach the image location. Usually for Vamtam Beaver Builder columns' background images or for default and local theme's background images - Page Title Background, Featured Area Background, Footer Widget Areas Background, etc.
This image is set as the column background image - click on the "VamTam Builder" link of the Wordpress Toolbar:
Click on the element's column settings:
When you open the settings panel, you can see the image sizes:
Here's an example for a local Page Title Background image - click on the "Edit Page" link of the Wordpress Toolbar:
You can locate that image in the Local page's VamTam options and then you can proceed with Step 1: