Google has announced, via its online blog, that is has begun to give users the option to purchase extra online storage via Google Checkout.

At the moment Google gives free online storage with relevant services, currently 1GB for Picasa Web Albums and around 2.8GB for Gmail.

When Google launched Gmail, the generous storage capacity was pretty revolutionary at the time - since then, other online mail services have upped their offerings to compete.

"We'll be rolling out extra storage that you can purchase to use across several Google products (today, Picasa Web Albums and Gmail; soon, other applications like Google Docs & Spreadsheets)."

"That will help make storage really useful, like letting you upload lots of full resolution images to Picasa Web Albums."

When you reach the limit of free storage ... consider this your overflow solution", states the blog.

The prices will be 6GB for $20 a year, 25GB for $75 a year, 100GB, $250 a year and 250GB for $500 a year.

This could be seen as a move towards the rumoured "GDrive" back up service that would act like an online hard drive, a sort of network that would work on any computer, operating systems or device.