[Theme Multi-Color] warning message when updating

“Warning: Cannot modify header information – headers already sent by”

almost always means a blank line before or after the opening or closing php tags.

The code I’m dealing with follows:

[ Moderator Note: Please post code or markup snippets between backticks or use the code button. Please don’t use blockquote. ]

/* Supporting validation functions */
function mc_validate_color($color) {
    $exp = "/([A-Za-z0-9])/";
    if(!preg_match($exp,$color))
        return false;
    else
        return true;
}

function mc_validate_image_url($url) {
    $exp = "/^https?:\/\/(.)*\.(jpg|png|gif|ico)$/i";
    if(!preg_match($exp,$url))
        return false;
    else
        return true;
}

function mc_validate_image_size($url,$width,$height) {
    $size = getimagesize($url);
    if($size[0] > $width or $size[1] > $height)
        return false;
    else
        return true;
}

If anyone can help me understand what the specific problem is here, I’d greatly appreciate it. Please let me know if you need me to post the entire page of code.

Thanks in advance!