This worked for me.
#!/usr/local/bin/perl
BEGIN {
$| = 1;
$^W = 1;
}
use strict;
use warnings;
use Tk;
use Tk::Splashscreen;
use Tk::widgets qw/Photo/;
my $ssw = MainWindow->new;
$ssw->Button(
-text => 'Quit',
-command => \&exit,
)->pack;
my $sp= $ssw->Splashscreen(-milliseconds => 5000);
my $giffer = '/path/to/some.gif';
$sp->Label(
-image => $ssw->Photo(
-file => $giffer,
))->pack;
$sp->Splash;
$ssw->after(1000);
print "Waiting for Splashscreen to finish...\n";
$sp->Destroy;
$ssw->deiconify;
MainLoop;