You are saving your PNG both to an image file (file.gif, which has the wrong extension, it should be file.png) and printing it to STDOUT, where it gets sent to the browser.

If you want to send your image directly to the browser, then you'll need to send it to STDOUT with a proper content-type header: 

print "Content-type: image/png\n\n";
print $gd->png;

[download]

If you want to save the image on your server and tell the browser to display it, then use: 

open IMG, '>file.png';
print IMG $gd->png;
close IMG;
print "Content-type: text/html\n\n";
print '<img src="http://yourserver.com/file.png">';

[download]

UpdateFixed typo in content-type.

In reply to Re: GD graphs and CGI by friedo
in thread GD graphs and CGI by Anonymous Monk

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.