diff --git a/workflow-parser/src/workflow-v1.0.json b/workflow-parser/src/workflow-v1.0.json
index 5e24de2c..8efa58fc 100644
--- a/workflow-parser/src/workflow-v1.0.json
+++ b/workflow-parser/src/workflow-v1.0.json
@@ -1710,7 +1710,11 @@
           "concurrency": "job-concurrency",
           "outputs": "job-outputs",
           "defaults": "job-defaults",
-          "steps": "steps"
+          "steps": "steps",
+          "snapshot": {
+            "type": "snapshot",
+            "description": "snapshot for custom image"
+          }
         }
       }
     },
@@ -2522,6 +2526,12 @@
       "string": {
         "require-non-empty": true
       }
+    },
+    "snapshot": {
+      "description": "snapshot for custom image",
+      "string": {
+        "require-non-empty": true
+      }
     }
   }
 }
diff --git a/workflow-parser/testdata/reader/snapshot.yml b/workflow-parser/testdata/reader/snapshot.yml
new file mode 100644
index 00000000..4ca24958
--- /dev/null
+++ b/workflow-parser/testdata/reader/snapshot.yml
@@ -0,0 +1,34 @@
+include-source: false # Drop file/line/col from output
+---
+on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    snapshot: custom-image
+    steps:
+      - run: echo hi
+---
+{
+  "jobs": [
+    {
+      "type": "job",
+      "id": "build",
+      "name": "build",
+      "if": {
+        "type": 3,
+        "expr": "success()"
+      },
+      "runs-on": "ubuntu-latest",
+      "steps": [
+        {
+          "id": "__run",
+          "if": {
+            "type": 3,
+            "expr": "success()"
+          },
+          "run": "echo hi"
+        }
+      ]
+    }
+  ]
+}
\ No newline at end of file