IIRC, the iconimage accepts the Pixmap object, not Photo. I've always had success with the xpm format.

Update: Here's an example: 

#!/usr/bin/perl
use strict;
use warnings;

use Tk qw{ MainLoop };

my $mw = 'MainWindow'->new;
$mw->iconimage($mw->Pixmap(-data => << '__XPM__'));
/* XPM */
static char * pm_xpm[] = {
"32 32 4 1",
"     c black",
".    c blue",
"X    c yellow",
"o    c red",
"                                ",
" .............................. ",
" .............................. ",
" .............................. ",
" .............................. ",
" .............................. ",
" .............................. ",
" .............................. ",
" .............................. ",
" ..........ooooooo............. ",
" ........ooooooooooo........... ",
" .......oo.........oo.......... ",
" ......oo...XXXXX...oo......... ",
" .....oo...X.....X...oo........ ",
" .....oo..X.......X..oo........ ",
" .....oo..X.......X..oo........ ",
" .....oo...X.....X...oo........ ",
" ......oo...XXXXX...oo......... ",
" .......oo.........oo.......... ",
" ........ooooooooooo........... ",
" ..........ooooooo............. ",
" .............................. ",
" .............................. ",
" .............................. ",
" .............................. ",
" .............................. ",
" .............................. ",
" .............................. ",
" .............................. ",
" .............................. ",
" .............................. ",
"                                "};
__XPM__
MainLoop();

[download]

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

In reply to Re: PerlTk GNOME3 alternate icon file shown as blank square by choroba
in thread PerlTk GNOME3 alternate icon file shown as blank square by kaza_perl_ip

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.