diff --git a/build.sh b/build.sh
index 955a6e4..213be84 100755
--- a/build.sh
+++ b/build.sh
@@ -144,6 +144,7 @@ fi
 
 export USE_QEMU="${USE_QEMU:-0}"
 export IMG_DATE="${IMG_DATE:-"$(date +%Y-%m-%d)"}"
+export IMG_FILENAME="${IMG_FILENAME:-"${IMG_DATE}-${IMG_NAME}${IMG_SUFFIX}"}"
 
 BASE_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 export SCRIPT_DIR="${BASE_DIR}/scripts"
diff --git a/export-image/03-set-partuuid/00-run.sh b/export-image/03-set-partuuid/00-run.sh
index 29edc67..e166e97 100755
--- a/export-image/03-set-partuuid/00-run.sh
+++ b/export-image/03-set-partuuid/00-run.sh
@@ -1,6 +1,6 @@
 #!/bin/bash -e
 
-IMG_FILE="${STAGE_WORK_DIR}/${IMG_DATE}-${IMG_NAME}${IMG_SUFFIX}.img"
+IMG_FILE="${STAGE_WORK_DIR}/${IMG_FILENAME}.img"
 
 IMGID="$(dd if="${IMG_FILE}" skip=440 bs=1 count=4 2>/dev/null | xxd -e | cut -f 2 -d' ')"
 
diff --git a/export-image/04-finalise/01-run.sh b/export-image/04-finalise/01-run.sh
index cd284ac..eee9c5c 100755
--- a/export-image/04-finalise/01-run.sh
+++ b/export-image/04-finalise/01-run.sh
@@ -1,7 +1,7 @@
 #!/bin/bash -e
 
-IMG_FILE="${STAGE_WORK_DIR}/${IMG_DATE}-${IMG_NAME}${IMG_SUFFIX}.img"
-INFO_FILE="${STAGE_WORK_DIR}/${IMG_DATE}-${IMG_NAME}${IMG_SUFFIX}.info"
+IMG_FILE="${STAGE_WORK_DIR}/${IMG_FILENAME}.img"
+INFO_FILE="${STAGE_WORK_DIR}/${IMG_FILENAME}.info"
 
 on_chroot << EOF
 /etc/init.d/fake-hwclock stop
diff --git a/export-image/prerun.sh b/export-image/prerun.sh
index ed17dbe..5f003fa 100755
--- a/export-image/prerun.sh
+++ b/export-image/prerun.sh
@@ -1,6 +1,6 @@
 #!/bin/bash -e
 
-IMG_FILE="${STAGE_WORK_DIR}/${IMG_DATE}-${IMG_NAME}${IMG_SUFFIX}.img"
+IMG_FILE="${STAGE_WORK_DIR}/${IMG_FILENAME}.img"
 
 unmount_image "${IMG_FILE}"