Problem
You want to generate a vertical image, with text over the top.
Solution
Here is some code I wrote, which is used extensively on my sites:
Example
Reference
Give it a blast on this site, like this: http://coding-school.com/common/label-up.php?label=your+text+here
Automatically calculates size required. You can also add font=# – where # is 1 to 5, like this:
http://coding-school.com/common/label-up.php?label=your+text+here&font=3