diff --git a/diskimage-create/diskimage-create.sh b/diskimage-create/diskimage-create.sh
index e3ef092513..e0ef9472c8 100755
--- a/diskimage-create/diskimage-create.sh
+++ b/diskimage-create/diskimage-create.sh
@@ -32,7 +32,7 @@ usage() {
     echo "            [-k <kernel package name> ]"
     echo "            [-l <log file> ]"
     echo "            [-n]"
-    echo "            [-o **amphora-x64-haproxy** | <filename> ]"
+    echo "            [-o **amphora-x64-haproxy.qcow2** | <filename> ]"
     echo "            [-p]"
     echo "            [-r <root password> ]"
     echo "            [-s **2** | <size in GB> ]"
@@ -243,7 +243,7 @@ elif [ "${AMP_BASEOS}" = "fedora" ]; then
     export DIB_RELEASE=${AMP_DIB_RELEASE:-"28"}
 fi
 
-AMP_OUTPUTFILENAME=${AMP_OUTPUTFILENAME:-"$PWD/amphora-x64-haproxy"}
+AMP_OUTPUTFILENAME=${AMP_OUTPUTFILENAME:-"$PWD/amphora-x64-haproxy.qcow2"}
 
 AMP_IMAGETYPE=${AMP_IMAGETYPE:-"qcow2"}
 
@@ -520,4 +520,4 @@ if [ -z "$DIB_REPOREF_amphora_agent" ]; then
 else
     echo "Successfully built the amphora using the $DIB_REPOREF_amphora_agent amphora-agent."
 fi
-echo "Amphora image size: `stat -c "%n %s" $AMP_OUTPUTFILENAME.$AMP_IMAGETYPE`"
+echo "Amphora image size: `stat -c "%n %s" $AMP_OUTPUTFILENAME`"
diff --git a/releasenotes/notes/diskimage-create-add-file-extension-to-default-34eeaa97b788cc67.yaml b/releasenotes/notes/diskimage-create-add-file-extension-to-default-34eeaa97b788cc67.yaml
new file mode 100644
index 0000000000..3449cf9f8d
--- /dev/null
+++ b/releasenotes/notes/diskimage-create-add-file-extension-to-default-34eeaa97b788cc67.yaml
@@ -0,0 +1,11 @@
+---
+upgrade:
+  - |
+    The default for the output file has been changed in
+    diskimage-create.sh. It is now amphora-x64-haproxy.qcow2 instead of
+    amphora-x64-haproxy.
+fixes:
+  - |
+    diskimage-create.sh used $AMP_OUTPUTFILENAME.$AMP_IMAGETYPE for
+    constructing the image file path when checking the file size, which was
+    not correct and caused an "No such file or directory" error.