cache the images
diff --git a/tools/build_kvm.sh b/tools/build_kvm.sh
index 32c7bf6..d804f42 100755
--- a/tools/build_kvm.sh
+++ b/tools/build_kvm.sh
@@ -284,6 +284,15 @@
     cp_it ~/.bashrc $ROOTFS/$DEST/.bashrc
 fi
 
+# pre-cache uec images
+for image_url in ${IMAGE_URLS//,/ }; do
+    IMAGE_FNAME=`basename "$image_url"`
+    if [ ! -f $IMAGES_DIR/$IMAGE_FNAME ]; then
+        wget -c $image_url -O $IMAGES_DIR/$IMAGE_FNAME
+    fi
+    cp $IMAGES_DIR/$IMAGE_FNAME $ROOTFS/$DEST/devstack/files/images
+fi
+
 # Configure the runner
 RUN_SH=$ROOTFS/$DEST/run.sh
 cat > $RUN_SH <<EOF