Huge backups after moved to Azure using Backup to Azure tool

Hi there.

I have couple of servers with SQL Server 2008R2 and use Backup to Azure tool for upload database backup to Azure storage.

I have the database with the name iDatabase, it has size approx 5GB but after backup successfully done and moved to Azure

the size increased to 1024GB. As I understand the backup size must be less. Do you have any idea what the problem is?