In your screenshoot, the memory-limit is set to 64M. To be able to re-size the image, the GD Library will need to make use of much more memory on the server.
you will need to increase the memory_limit to 256M. The GD library will quite a bit of the servers memory when resizing the images, especial if you are resizing the image a number of times.
your screen shot also shows a max_execution_time of 60 seconds. This setting is the limit on how long a PHP script can execute, if it takes longer than 60 seconds to upload the image and re-size them, the script will time out.
You will need to increase this setting in the PHP.ini file.
If you need assistance modifying the PHP.ini settings, you should consult with your host.
