Update ContentLink

So, I have created a custom profile and it is not time to update or set a profile item called CompanyImage. I have taken care of the upload into the Image Library. GetValue returns an image link  which has a childItemId that points at an image. When I update the childItemId and save nothing updates. I don't know how to create a new content link or set he image any other way. This is way too difficult and there seems to be no documentation.