If you send the email with attachments and a number of addresses, the email gets uploaded once and distributed from the Email server to each address. If they all exist on one server, they each get a copy of the attachment in thier mail stores until downloaded.

There are various ways that the amount of space can be handled. You can have a personal limit, once that is exceeded new emails result in failure with due to mail box full. You can also have a group quota. For example a company account might have a limit of x amount of disk space. Again if it is all used then rejection becuase mail box is full.

In the first case, I can clean out my mail box to free up space, in the second I must get others to clean up there mail box to free up space.

If you send 20 people the email in same company in the second situation, then it is likely that their mail space require 20 x the file size.

With large files it is often better to store them in a public folder and send people links. Now you ensure that only one copy is out there, People with slow connections can choose when / or if they want to download the file, even those with fast connections can decide if this is a good time to download the file.

PM