Yes!
As an admin, you can upload custom backgrounds which your agents will be able to use once on a call.
To upload a new one, head to your SnapCall Dashboard, click on settings on the left side of the screen. On the submenu, click on 'General'.
Once there, look for the 'Preference' tab, you will then find the option as shown on the screenshot above.
While upload your image, SnapCall will also tell you which resolution is the suggested one, as well as which image format are supported.