diff --git a/app/main.py b/app/main.py
index 152ef43..55640e7 100644
--- a/app/main.py
+++ b/app/main.py
@@ -167,6 +167,7 @@ def _build_acquisitions():
d["gp_label"] = gp_label.get((j["acquisition_id"], j["auv"], j["gopro_serial"]), "?")
d["video_duration_fmt"] = _fmt_dur(int(j["video_duration_s"] or 0)) if (j["video_duration_s"] or 0) > 0 else "—"
d["trimmed_total"] = (j["trimmed_head"] or 0) + (j["trimmed_tail"] or 0)
+ d["has_thumbnail"] = (DB_PATH.parent / "thumbnails" / f"job_{j['id']}.jpg").exists()
# Only expose a native viser link when port is listening. Probed on render via TCP check.
d["native_viser_url"] = None # filled below
by_acq.setdefault(j["acquisition_id"], []).append(d)
@@ -392,6 +393,16 @@ async def view_job(job_id: int):
return {"url": f"http://{worker['host']}:{port}"}
+@app.get("/jobs/{job_id}/thumbnail")
+async def job_thumbnail(job_id: int):
+ """Serve the cached thumbnail the dispatcher scp'd after trimming out-of-water frames."""
+ from fastapi.responses import FileResponse
+ thumb = DB_PATH.parent / "thumbnails" / f"job_{job_id}.jpg"
+ if not thumb.exists():
+ raise HTTPException(404, "no thumbnail yet")
+ return FileResponse(thumb, media_type="image/jpeg")
+
+
@app.post("/jobs/{job_id}/live")
async def live_job(job_id: int):
"""Return the URL of demo.py's native viser (PointCloudViewer with camera frustums,
diff --git a/app/static/style.css b/app/static/style.css
index f43ac2a..46c4163 100644
--- a/app/static/style.css
+++ b/app/static/style.css
@@ -127,3 +127,5 @@ code { background: rgba(255,255,255,0.05); padding: 0 0.25rem; border-radius: 3p
.job-item .viser-link:hover { background: var(--accent, #4a9); color: white; }
.job-item.skipped { opacity: 0.55; }
.job-item.skipped .label { font-style: italic; }
+
+.job-item .thumb { width: 48px; height: 27px; object-fit: cover; border-radius: 3px; margin-right: 4px; }
diff --git a/app/templates/_jobs_table.html b/app/templates/_jobs_table.html
index 648c369..45a7925 100644
--- a/app/templates/_jobs_table.html
+++ b/app/templates/_jobs_table.html
@@ -18,6 +18,7 @@
{% else %}■{% endif %}
+ {% if j.has_thumbnail %}
{% endif %}
#{{ j.id }}
{{ j.auv }} {{ j.gp_label }}
{{ j.segment_label }}
diff --git a/scripts/__pycache__/dispatcher.cpython-311.pyc b/scripts/__pycache__/dispatcher.cpython-311.pyc
index 3ea3824..dda077b 100644
Binary files a/scripts/__pycache__/dispatcher.cpython-311.pyc and b/scripts/__pycache__/dispatcher.cpython-311.pyc differ
diff --git a/scripts/dispatcher.py b/scripts/dispatcher.py
index 4e4e730..41d45ce 100644
--- a/scripts/dispatcher.py
+++ b/scripts/dispatcher.py
@@ -379,6 +379,25 @@ def do_extract(job: sqlite3.Row, worker: dict) -> str:
print(f" ↳ job #{job['id']}: only {remaining} underwater frames (<{min_frames}) — marking skipped")
set_status(job["id"], status="skipped", error=f"too short: {remaining} underwater frames")
raise RuntimeError("skipped_short")
+ # Copy the first kept frame back to the dashboard host as a thumbnail so the UI can show
+ # what the job actually sees. Mid-point would be better but first is cheap and on disk now.
+ thumb_dir = DB_PATH.parent / "thumbnails"
+ thumb_dir.mkdir(exist_ok=True)
+ thumb_local = thumb_dir / f"job_{job['id']}.jpg"
+ subprocess.run(
+ ["scp", "-o", "BatchMode=yes",
+ f"{worker['ssh_alias']}:{frames_dir}/frame_*.jpg", str(thumb_local)],
+ capture_output=True, timeout=30,
+ ) # globbing only picks 1 on the remote side via shell expansion
+ # If glob scp is empty, try first explicit by listing
+ if not thumb_local.exists() or thumb_local.stat().st_size == 0:
+ rc, out, _ = ssh(worker["ssh_alias"], f"ls {shlex.quote(frames_dir)}/frame_*.jpg 2>/dev/null | head -1")
+ first = out.strip()
+ if first:
+ subprocess.run(
+ ["scp", "-o", "BatchMode=yes", f"{worker['ssh_alias']}:{first}", str(thumb_local)],
+ capture_output=True, timeout=30,
+ )
# Trim once per job so LVM thin pool on the host actually reclaims the freed blocks.
ssh(worker["ssh_alias"], "sudo fstrim / 2>/dev/null || fstrim / 2>/dev/null", timeout=60)
return frames_dir