Yahoo has launched a beta of its webmail service that aims to make it easier to share photos online.

Sending digital photos by email can clog up inboxes and involve long download times, but the Yahoo Photomail service inserts only a thumbnail of the image in the email.

When users click on the image they are directed to a Yahoo server hosting a high resolution version.

The service requires users to install a small piece of software. They can then drag and drop up to 300 pictures into an email, after which the service automatically does the necessary resizing.

Photomail enables users to send pictures stored on their computers as well as images from their Yahoo Photo accounts and pictures found through Yahoo Picture Search.

The Photomail beta is available here. It requires Internet Explorer 5.5 or higher running on Windows 2000 or XP.

Yahoo also revealed that it has enhanced its online mail service by implementing the DomainKeys authentication technology.

The technique helps to weed out spam and phishing emails by providing additional information about the origin of a message. This enables a user to verify whether the address in the 'from' line of the email is genuine.