Hi Sarah!
Thanks for reaching out to us! Let me help you with that issue.
I have just tried to make an import from Eventbrite and it imported the image for me, so there might be some conflict somehow.
It’s good you tried deactivating all other plugins. Could you please try switching to a default theme (like twenty seventeen) and then try importing the event again to see if any difference?
If no difference, please share with us (in a private reply if you’d like) a link to the Eventbrite event you are trying to import so we can try to spot anything strange with it.
Let me know how that goes.
Thanks,
Victor