You can add files to your calendar events from your local computer storage and cloud-based file storage services such as Dropbox. Here's how to add files from other major cloud file storage services, including Google Drive, Microsoft's OneDrive, Box, etc.
Here is part of an event page with a mountain image in the Description field. The image is linked from Dropbox.
There's also a team photo in the Attachments field, which was uploaded from local computer storage.
You can link files from Dropbox without uploading them to Teamup. In the Description field, click the Dropbox icon in the toolbar:
Link to files from other sources
You can also insert direct links from Google Drive or elsewhere straight to your event Description field or a custom text field.
Click the Upload icon in the Description field or the Upload text in the Attachment field:
From the pop up, select your source:
You may be prompted to log into your chosen file source to access the files. If needed, you can switch to a different account for any source.
You can paste an image directly into a Teamup event.