As you may know that using Capture Role REST Service Management API you can create a Virtual Machine Image to your image gallery directly from a running virtual machine which is described at the link below:

• http://msdn.microsoft.com/en-us/library/windowsazure/jj157201.aspx

In above MSDN documentation the Request URI is defined as below which is incorrect:

POST    https://management.core.windows.net/<subscription-id>/services/hostedservices/<service-name>/deployments/<deployment-name>/roles/<role-name>/Operations
 

The correct Request URL should be as below:

POST    https://management.core.windows.net/<subscription-id>/services/hostedservices/{serviceName}/deployments/{deploymentName}/RoleInstances/{roleInstanceName}/Operations