How to send an image or attachment in Microsoft Teams Chat

As per the Teams API documentation,

Send a message with a file attachment

The file to attach must already be stored in SharePoint. To retrieve the file properties, you need to GET the driveItem for the file. The eTag of the driveItem contains a GUID which serves as your attachment ID. The webDavUrl of the driveItem is your attachment contentURL. You can use the driveItem's name as your attachment name. You can use /drives/{drive-id}/items/{item-id} to obtain a drive item resource. To get the webDavUrl, you must explicitly select it using $select=webDavUrl or $select=*,webDavUrl.
Microsoft Graph supports the OpenUrl card action. Bots are required for other card actions.

For further details, refer to Send chatMessage in a channel or a chat - Microsoft Graph beta | Microsoft Learn

If the external service provides a Developer API Reference/Documentation, you should be able to integrate the endpoints in callin.io using the app’s universal module (Make an API call) or the generic HTTP “Make a request” module.

You can also submit this suggestion to the Idea exchange, under App improvement ideas.

Remember to search for it first to ensure you don't create a duplicate suggestion.

If you require assistance with setting up the app’s universal module or the generic HTTP module, please provide more details about your attempts regarding the external service’s Developer API Reference – including how you are configuring the connection, a link to the endpoint you are trying to connect to, and any errors you are encountering.