File size

Both PHP and drupal impose limits on the file size of attachments. To edit the default settings:

Administer > Site Configuration > File Uploads

Here you can set the default size for your attachments. At the bottom you would see something like:

Your PHP settings limit the maximum file size per upload to 2 MB.

You cannot define a value greater than this value in your Default maximum file size per upload field. This value is defined by the upload_max_filesize in the php.ini

upload_max_filesize = 2M

You can change this to any positive integer, 50 for example. Remember to backup your php.ini file before you edit it.

File types

For sound security reasons every file type is not allowed in an attachment. The allowed attachments are listed in Default permitted file extensions field on the following page.

Administer > Site Configuration > File Uploads

You can edit Default permitted file extensions field to add or remove file extensions.