cookies and subdomains

[apepelis]

I'm lazy and I'm just going to do this easy.
I have the user validate and login in, then the logged in page loads imgs that log the user into a subdomain.

so..
the log in page looks like:

You're in, so go for it.<br><a href='main.php'>Click here for main page</a><br>
<img src='loginsub.php?nickname=dog'>

this is loginsub.php:

<?php
function deleteTheseCookies()
{
setcookie("site_user_sub", $nick, time() -1);
}
function setTheseCookies($nick)
{
setcookie("site_user_sub", $nick, time() + 31536000, "/");
}
if($logout)
{
deleteTheseCookies();
}
else
{

setTheseCookies($nickname);
}
php?>

and I get a red X cause I don't send it image data.
but when I try to get it to send image data, it doesn't load the cookie. how would I do this?
tia

[ereptur]

you can use a domain name instead of a path in the setcookie function like so:

setcookie("site_user_sub", $nick, time() + 31536000, ".yourdomain.com"); 

[apepelis]

yeah, but my problem is that I need to have this message return an image...
how does a file set a header content for html (ie a cookie)
but also return an image?

[ereptur]

after using setcookie, you would use header() like:

header("Content-Type: image/jpeg");

then just write your image file out

[apepelis]

yeah... but you can't write out both the content header for a jpeg AND a cookie.. not that I've been able to do.. a cookie is header info for a content type of text/html. and it messes up a jpeg is your put it in the header of it.