It looks like it is possible to setup some icons in a panel :
https://userbase.kde.org/images.userbas ... nel-45.gif

I tried it with an image, but it does not work.it works only with menu icons from the panel.

do I need to write a .desktop file ? or a plasmoid ?

I can with a desktop file display an icon, but I can not adapt the size.

Few ways...

1) Change the 'Application Launcher' logo

Right click the launcher...




2) Add the logo to the KDE menu and then add the logo to the panel.

Right click the launcher...


Full image: http://i.imgur.com/AgN5mXI.png

3) Edit the plasma theme - panel background.

More of the plasma5 themes:
- https://techbase.kde.org/Development/Tu ... asma/Theme
- https://techbase.kde.org/Development/Tu ... emeDetails


Full image (plasma4): http://i.imgur.com/dhhrl.png

4) Write a small plasma widget

Using as template: https://www.kubuntuforums.net/showthrea ... post369248
KDE TechBase: https://techbase.kde.org/Development/Tu ... ingStarted

Thanks for your reply.

few questions ,
regarding solution 2, I think you may not be able to set the width of your icon as needed.It will be stretched. (I tried a .desktop file)
may be solution 4, has the same problem (plasma widget) ?

solution 3:
Yes, I would like being able doing this, if I manage to create a theme based on breeze dark theme.
I have found some documentations, but none regarding the way to derivate from breeze dark theme.
I may open another thread