• binmode STDOUT; is not necessary, if you are generating HTML.
• Images are typically stored in a separate directory - typically '/images'
• Web server (apache) permissions for cgi-bin allow program execution but usually do not allow content display

You may want to move your image to a different directory, then try to display it using plain HTML.

After that succeeds, you can include that HTML in your perl code.

More typically, the cgi-bin script would read the image, and render it directly, but the cgi-bin script would be called from HTML, so the image , which is dynamically generated is embedded in a web page.