Hi Robert!
Thanks for getting in touch with us!
Unfortunately, there is no built in functionality to set a default image for an import. You could, however, achieve something like similar with some custom coding.
We are fairly limited in how much support we can give for custom development questions as we state here > https://theeventscalendar.com/knowledgebase/what-support-is-provided-for-license-holders/
But, if you decide to go for the customization and have any questions, don’t hesitate to ask and I’ll be happy to help as much possible.
Best,
Victor