nettuts image upload and resize

[eluser]happyeddie[/eluser]
I've tried running the example code from:

http://net.tutsplus.com/videos/screencas...ipulation/

But some images that are above 800kb won't resize but upload just fine.

Is this a file system (mac osx with MAMP) issue or a CI config setting error?

I want to be able to change the image size of image that are larger than 2 meg.