I tried uploading my own PNG and it worked fine for me.
I get similar when I print ‘win’ so I’m sorry it’s not working for you.
javax.swing.JFrame[frame0,-9,-9,1938x1028,invalid,layout=java.awt.BorderLayout,title=TestProject (STAGING),
resizable,maximized,defaultCloseOperation=DO_NOTHING_ON_CLOSE,
rootPane=javax.swing.JRootPane[,9,38,1920x981,invalid,layout=com.incors.plaf.alloy.bk,alignmentX=0.0,alignmentY=0.0,
border=,flags=16777673,maximumSize=,minimumSize=,preferredSize=],rootPaneCheckingEnabled=true]