Base64 encoding was used primarily to send attachments with emails when MIME format did not deal with unreadable characters. All the attachments had to be converted in base64 format before they could be transferred through email because MIME format had conflict with those characters. Now this is automatically done. When you attach a file with your email message, the file is automatically converted to Base64 so that it can be transferred. And when the recipient downloads the file, it is converted back to its original format.
This means that we break all the 8 bit bytes to 6 bit bytes. This provides an extra byte over every three bytes. This shows that the file size will increase and this is the reason why the attachments are always increased in size.
This program provides a complete graphical interface to look like a wizard which makes conversion easy, understandable and manageable.