my $mw = MainWindow->new ();
    $mw->Icon(-image => $mw->Pixmap(-data => &tart_icon));

[...]

sub tart_icon {
    return <<EOI
/* XPM */
static char * Icon_xpm[] = {
"32 32 4 1",
"     c #000000000000",
"g    c #00FF00",
"X    c #FF0000",
"D    c #FFFF00",

# 32 lines more with the inline pixmap
[...]