New feature: You can now upload a thumbnail to your place, that will persist through updates.
You can access this through your place settings. There is a link called "Manage Thumbnail" that will take you to the thumbnail management page:
From there, you have the option to re-render your place thumbnail if you don't have a custom thumbnail, or to delete your custom thumbnail if you do have a custom thumbnail.
Uploading will cost 10 Dius regardless of whether you already have a custom thumbnail or not. The image should be automatically resized.
Have fun. We are Finobe.