Is it possible to put another image other than spark?
Not sure if i understand you completely. Are you talking about the yellow-red spark icon, which is shown in the system tray and taskbar? You can change that if you have programming skills and want to compile your own version (it is not possible to change that via setting). Spark’s source is available here GitHub - igniterealtime/Spark: Cross-platform real-time collaboration client optimized for business and organizations.