Use compressed image file as artifact

Bug: 363237196
Test: will be tested in kokoro
Change-Id: Ief788c710ed101e3c4e2a0d846256601e85c341b
diff --git a/build/debian/kokoro/gcp_ubuntu_docker/build.sh b/build/debian/kokoro/gcp_ubuntu_docker/build.sh
index 4598d1c..4cc4769 100644
--- a/build/debian/kokoro/gcp_ubuntu_docker/build.sh
+++ b/build/debian/kokoro/gcp_ubuntu_docker/build.sh
@@ -6,4 +6,4 @@
 sudo losetup -D
 grep vmx /proc/cpuinfo || true
 sudo ./build.sh
-cp image.raw ${KOKORO_ARTIFACTS_DIR}
+tar czvS -f ${KOKORO_ARTIFACTS_DIR}/image.tar.gz image.raw
diff --git a/build/debian/kokoro/gcp_ubuntu_docker/continuous.cfg b/build/debian/kokoro/gcp_ubuntu_docker/continuous.cfg
index 111096d..97ebd5d 100644
--- a/build/debian/kokoro/gcp_ubuntu_docker/continuous.cfg
+++ b/build/debian/kokoro/gcp_ubuntu_docker/continuous.cfg
@@ -8,6 +8,6 @@
 
 action {
   define_artifacts {
-    regex: "image.raw"
+    regex: "image.tar.gz"
   }
 }
diff --git a/build/debian/kokoro/gcp_ubuntu_docker/hourly.cfg b/build/debian/kokoro/gcp_ubuntu_docker/hourly.cfg
index 111096d..97ebd5d 100644
--- a/build/debian/kokoro/gcp_ubuntu_docker/hourly.cfg
+++ b/build/debian/kokoro/gcp_ubuntu_docker/hourly.cfg
@@ -8,6 +8,6 @@
 
 action {
   define_artifacts {
-    regex: "image.raw"
+    regex: "image.tar.gz"
   }
 }