"Don't fancy digiKam's default splash screen? No
problem, you can easily replace it with your own photo. First off,
you need to prepare your own photo for use in the splash screen. To
do this, use an image editing application like the GIMP to resize
the photo you want to 500×307 pixels. Save the resized image
in the PNG format. Next, grab the splash-digikam.svgz file from
digiKam's source code repository and open the downloaded file in
the Inkscape vector graphics editor."