After upgrading to ZP 1.5 zpArdoise will not display logo file, despite banniere1.jpg image still existing in same location as before upgrading.

When I look at the source code I see that the code for the logo/banner is commented (i.e. between ``)
Then of course the logo is not displayed.

Yes, you are right! I must have done some testing for mobile, and forgotten about the change. Sorry for false alarm. Works fine.