The first time you click the logo button, you will see instructions on how to add your own logo to display in Quelea. If you have already followed the instructions once, next time you click it, you will instead access the logo you have assigned. However, a tooltip is always available if you hover the mouse over the button if you would like a reminder on how to change the logo.
Setting or changing the logo
This is simple: all you need to do is to right-click the logo button and you will be able to browse to the desired image. This image can later be used as an alternative to fade into, rather than fading to background image/colour/video or a blank screen.