I added links to various planner tasks last week and all seemed fine, with small icon on the task card.
Opened the planner this morning and the link icon now shows as a large header on each task card.
I can't see why this has happened, or a way other than to untick "show on card" (which defeats the purpose of showing), to remove the image.
Latest Teams version is running.
EDIT - Apparently this is behaviour by design, but not behaviour that had manifested itself when I added the attachment last week!
I just wish I could keep the mini icon without having the preview picture as it is a neat and quick way of opening the attachment.