Simple Captcha - files still in "/tmp" directory and not displaying

I'm trying to use the Rails3 Simple Captcha version from here:
http://github.com/galetahub/simple-captcha

It's working 100% fine on my local environment.

In Production, I had to point the "convert" command to the correct
directory and then reinstall ImageMagick with the FreeType lib.

Now I'm not getting any errors in production.log but the images are
coming up as broken images.

Any ideas?

I'm starting to narrow down the problem.

The files are being created in the "/tmp" folder.

But when image.rb passes it up to simple_captcha_controller.rb, the
files are coming through empty.

The versions in "/tmp" are not empty files though.

I'm using a CentOS server I configured myself (rather than a Rails
host like EngineYard) so I'm guessing it's some sort of server
issue.

Found the solution:
https://rails.lighthouseapp.com/projects/8994/tickets/4063-rails-30-beta1-send_file-with-0-byte