Is it possible to reduce image size when shared

I understand you can make images available in lightroom cc using collections.  But I notice that this option uploads the full sized file to cc, thereby using up my limited cloud storage of 20gb, also also slows down the sync process.  I often use cc on a small screen tablet or phone.  Is there a way to upload lower resolution images to cc?  The images that I m making dealing with are all high res jpegs.