Yes, as a SnapCall admin you can select a custom background from the dashboard and make this the default one.
This means that when an agent will join a call, the custom background will be automatically applied for them without the need for them to manually select it.
To define a custom background as the default one, head to the general settings of your workspace, from there select or upload a custom background under the option 'Custom virtual background' option. Once done, ensure the option 'Set as default for everyone' is active.
Custom background won't be applied for the customer, which will only have the option to select one of the standard one offered by SnapCall.