IAmazonEC2.CreateImage (CreateImageRequest)

This example creates an AMI from the specified instance and adds an EBS volume with the device name /dev/sdh and an instance store volume with the device name /dev/sdc.

To create an AMI from an Amazon EBS-backed instance

var client = new AmazonEC2Client();
var response = client.CreateImage(new CreateImageRequest 
{
    BlockDeviceMappings = new List<BlockDeviceMapping> {
        new BlockDeviceMapping {
            DeviceName = "/dev/sdh",
            Ebs = new EbsBlockDevice { VolumeSize = 100 }
        },
        new BlockDeviceMapping {
            DeviceName = "/dev/sdc",
            VirtualName = "ephemeral1"
        }
    },
    Description = "An AMI for my server",
    InstanceId = "i-1234567890abcdef0",
    Name = "My server",
    NoReboot = true
});

string imageId = response.ImageId;