Add DeleteImageById
diff --git a/images.go b/images.go
index 61a3369..a23e0bb 100644
--- a/images.go
+++ b/images.go
@@ -37,6 +37,20 @@
 	return is, err
 }
 
+func (gsp *genericServersProvider) DeleteImageById(id string) error {
+	err := gsp.context.WithReauth(gsp.access, func() error {
+		url := gsp.endpoint + "/images/" + id
+		_, err := perigee.Request("DELETE", url, perigee.Options{
+			CustomClient: gsp.context.httpClient,
+			MoreHeaders: map[string]string{
+				"X-Auth-Token": gsp.access.AuthToken(),
+			},
+		})
+		return err
+	})
+	return err
+}
+
 // ImageLink provides a reference to a image by either ID or by direct URL.
 // Some services use just the ID, others use just the URL.
 // This structure provides a common means of expressing both in a single field.