Basic example for PyQt5. You can also replace the image background by a solid color with QtGui.QPalette.
#!/usr/bin/python3
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
class Main(QtWidgets.QMainWindow):
def __init__(self):
super().__init__()
desktop = app.desktop().screenGeometry()
pixmap = QtGui.QPixmap('background.png')
pixmap = pixmap.scaled(desktop.width(), desktop.height())
self.splash = QtWidgets.QSplashScreen(pixmap)
self.splash.setWindowFlags(QtCore.Qt.WindowStaysOnTopHint | QtCore.Qt.FramelessWindowHint)
self.splash.setCursor(QtCore.Qt.BlankCursor)
self.splash.showFullScreen()
if __name__== '__main__':
app = QtWidgets.QApplication([])
gui = Main()
sys.exit(app.exec_())