web contact sheet problem

Hi

I have C17.1 with the canon sdk workaround

when I make a web contact sheet and click on the resultant images the image opens up to full size ( 4x bigger than the screen) regardless of what settings I try ie 600 to 2400 preview size

I take it that thumbnail means size of image on web page before you click on it
preview means size of image it opens up to when clicked on
what dose quality actually do

It would be great if I could find a setting that opened up to full screen not full size

thanks

robin