diff --git a/scripts/test_windows_input.ps1 b/scripts/test_windows_input.ps1
index 3c3a6e54..6ee042aa 100644
--- a/scripts/test_windows_input.ps1
+++ b/scripts/test_windows_input.ps1
@@ -333,6 +333,15 @@ try {
                         if ($case.kind -eq 'mode-transitions') { $null = Observer-Request $plan 'set-mode' $mode }
                         $row.capture_id = $end.id
                         $row.hex = $end.hex; $row.records = $end.records; $row.error = $end.error; $row.complete = $end.quiet_reached
+                        if ($case.kind -eq 'clipboard-image' -and $path -eq 'herdr-remote') {
+                            $capture = [Convert]::FromHexString([string]$end.hex)
+                            if ($capture.Length -ge 12) {
+                                $stagedPath = [Text.Encoding]::UTF8.GetString($capture, 6, $capture.Length - 12)
+                                if (Test-Path -LiteralPath $stagedPath -PathType Leaf) {
+                                    $row.staged_image_sha256 = (Get-FileHash -LiteralPath $stagedPath -Algorithm SHA256).Hash
+                                }
+                            }
+                        }
                         $row.final_outer_geometry = (Outer-State $plan).geometry
                         $row.status = 'observed'; $row.final_pane_geometry = $end.geometry
                         if ($path -in @('herdr', 'herdr-remote') -and (Test-Path -LiteralPath $plan.input_trace)) {
diff --git a/scripts/test_windows_input.py b/scripts/test_windows_input.py
index 4e111cbb..38868843 100644
--- a/scripts/test_windows_input.py
+++ b/scripts/test_windows_input.py
@@ -94,7 +94,10 @@ class WindowsInputGauntletTests(unittest.TestCase):
         empty_paste = b"\x1b[200~\x1b[201~"
         staged = b"\x1b[200~C:\\Temp\\herdr-clipboard-images-user\\image.png\x1b[201~"
         self.assertEqual(verdict(case, "legacy", {**self.evidence, "path": "direct", "hex": empty_paste.hex()})[0], "pass")
-        self.assertEqual(verdict(case, "legacy", {**self.evidence, "path": "herdr-remote", "hex": staged.hex()})[0], "pass")
+        remote = {**self.evidence, "path": "herdr-remote", "hex": staged.hex(),
+                  "staged_image_sha256": case["expected"]["legacy"]["sha256"]}
+        self.assertEqual(verdict(case, "legacy", remote)[0], "pass")
+        self.assertEqual(verdict(case, "legacy", {**remote, "staged_image_sha256": "0" * 64})[0], "fail")
         self.assertEqual(verdict(case, "legacy", {**self.evidence, "path": "herdr-remote", "hex": empty_paste.hex()})[0], "fail")
         self.assertEqual(verdict(case, "legacy", {**self.evidence, "path": "herdr", "hex": empty_paste.hex()})[0], "not_run")
 
diff --git a/scripts/windows_input/Native.cs b/scripts/windows_input/Native.cs
index 735d41a4..decbc58b 100644
--- a/scripts/windows_input/Native.cs
+++ b/scripts/windows_input/Native.cs
@@ -165,6 +165,7 @@ namespace HerdrInputGauntlet {
             } finally { CloseClipboard(); }
         }
         public static uint SetEmptyClipboardImage(IntPtr owner,string text) {
+            if(owner==IntPtr.Zero) throw new Exception("Clipboard owner is required");
             if(!OpenClipboard(owner)) throw new Exception("Clipboard busy; refusing replacement");
             IntPtr pngMemory=IntPtr.Zero,textMemory=IntPtr.Zero;
             bool complete=false;
diff --git a/scripts/windows_input/report.py b/scripts/windows_input/report.py
index 8f077cc7..d6c20803 100644
--- a/scripts/windows_input/report.py
+++ b/scripts/windows_input/report.py
@@ -79,7 +79,9 @@ def catalogue():
     ]:
         cases.append(dict(id=name, kind="paste", text=text, expected={mode: {"paste": text} for mode in MODES[1:]}))
     cases.append(dict(id="clipboard-image", kind="clipboard-image",
-                      expected={mode: {"clipboard_image": True} for mode in MODES[1:]}))
+                      expected={mode: {"clipboard_image": True,
+                                       "sha256": "4BA8D4FD5AB42544FEEFF22D50E84412502433CC95952FD1DF9A5293588DDBEA"}
+                                for mode in MODES[1:]}))
     cases.append(dict(id="clipboard-mixed", kind="clipboard-mixed", text="clipboard text wins",
                       expected={mode: {"paste": "clipboard text wins"} for mode in MODES[1:]}))
     cases.append(dict(id="mouse-interleave", kind="mouse-interleave", text="mouse\npaste",
@@ -223,8 +225,11 @@ def verdict(case, mode, evidence):
         except UnicodeDecodeError:
             return "fail", "Staged clipboard image path is not UTF-8"
         valid_path = re.fullmatch(r"[A-Za-z]:\\.*\\herdr-clipboard-images-[^\\]+\\[^\\]+\.png", path)
-        return (("pass", "Image-only clipboard was staged and its path reached the pane") if valid_path else
-                ("fail", "Pane did not receive a staged clipboard PNG path"))
+        if not valid_path:
+            return "fail", "Pane did not receive a staged clipboard PNG path"
+        return (("pass", "Exact clipboard PNG was staged and its path reached the pane")
+                if evidence.get("staged_image_sha256") == expected["sha256"] else
+                ("fail", "Staged clipboard image contents differ from the fixture"))
     if expected.get("mouse_interleave"):
         motion = rb"(?:\x1b\[<35;\d+;\d+M)+"
         newline = rb"(?:\r\n|\r|\n)"