No problem for the time, as always
Your correct.. this is a LinkedIn limitation. They only support fetching an 80x80 image with with the 'in' watermark embedded. Once imported, and scaled up, it can get a little grainy. Definitely better than nothing, but could definitely be better.
There's nothing we can do about this, but there are a lot of requests in their developer area for something larger. If it's ever implemented, we'll definitely support.
Hope that explains,
Alex