User authentification image url

Hi all, 

Trying my luck here as Dataverse is so linked to Dynamics. 

I have a PowerApps canvas application connected to Dataverse. In my table there is an image column. I have created the dynamic url in ly application so that the image launches in the browser when a user clicks on it (https://<organisation>.crm4.dynamics.com/Image/download.aspx?Entity=<TableName>&Attribute=<ColumnName>&Id=<LineID>&Full=true). The issue I am having is that the first time the link doesn't work because the user isn't authenticated. If the user clicks https://<organisation>.crm4.dynamics.com/ they are asked to log in and once this is done the url will work. My question is, how can I force this authentication so that the users can click on the image straight away ?

Thanks in advance for any help you can give.