Cronjob执行PHPMailer发送邮件时内嵌图片无法显示问题

The root cause here is almost always working directory mismatch between running the script via browser vs. cron. Let's break this down and fix it:

Why this happens #

When you run the script in a browser, PHP's working directory is the folder where your test2.php lives (/var/www/html/work/). So the relative path dedicated.png points to the correct file.

But cron jobs run with the executing user's default working directory (for root, that's usually /root/). When cron runs your script, it looks for dedicated.png in /root/ instead of /var/www/html/work/—hence the missing image.

Solutions to try #

1. Use an absolute path for the image #

Update your AddEmbeddedImage call to use the full absolute path of the image file. This is the most reliable method:

$mail->AddEmbeddedImage("/var/www/html/work/dedicated.png", "logoimg", "dedicated.png");

No matter where the script runs, it'll always point to the correct file location.

2. Change working directory in the cron command #

Modify your cron job to first navigate to the script's directory before executing it. This makes cron use the same working directory as when you run it in the browser:

* * * * * root cd /var/www/html/work && php test.php

The && ensures the php command only runs if the cd succeeds.

3. Set the working directory in your PHP script #

Add this line at the very top of your test2.php file to force PHP to switch to the script's directory when it runs:

// For PHP 5.3 and above
chdir(__DIR__);

// For older PHP versions
// chdir(dirname(__FILE__));

This way, any relative paths in your script will resolve correctly, regardless of where it's executed from.

Quick debugging tip #

To confirm the working directory issue, add this line to your script and check the output file after cron runs:

file_put_contents('/tmp/cron_working_dir.txt', getcwd() . PHP_EOL);

Open /tmp/cron_working_dir.txt—it'll show you exactly where cron is looking for files, which should confirm the path mismatch.

内容的提问来源于stack exchange，提问作者user9053749