diff --git a/download_imageset.py b/download_imageset.py
index 6c804be..fe35ab5 100755
--- a/download_imageset.py
+++ b/download_imageset.py
@@ -9,8 +9,8 @@ import os
 import re
 import struct
 import subprocess
-import sys
 import urllib.parse
+import zipfile
 from functools import partial
 from pathlib import Path
 from typing import Callable
@@ -413,37 +413,58 @@ def download_cmd(
 
 
 @cli.command("process")
-@click.argument("dirs", nargs=-1, required=True)
-def process_cmd(dirs: tuple[str, ...]) -> None:
-    for d in dirs:
-        p = Path(d)
+@click.argument("paths", nargs=-1, required=True, type=click.Path(path_type=Path))
+def process_cmd(paths: tuple[Path, ...]) -> None:
+    """Process directories and ZIP files, extracting ZIPs into sibling directories."""
+    for p in paths:
+        archive_path: Path | None = None
         if not p.exists():
-            print(f"skipping {p}: does not exist", file=sys.stderr)
+            logging.warning(f"skipping {p}: does not exist")
+            continue
+        if p.is_file() and p.suffix.lower() == ".zip":
+            output_dir = p.with_suffix("")
+            if output_dir.exists() and not output_dir.is_dir():
+                logging.warning(f"skipping {p}: {output_dir} is not a directory")
+                continue
+            try:
+                with zipfile.ZipFile(file=p) as archive:
+                    logging.info(f"extracting {p} → {output_dir}")
+                    archive.extractall(path=output_dir)
+            except zipfile.BadZipFile:
+                logging.warning(f"skipping {p}: invalid ZIP file")
+                continue
+            archive_path = p
+            p = output_dir
+        if not p.is_dir():
+            logging.warning(f"skipping {p}: expected a directory or ZIP file")
             continue
         if _needs_resize(p):
             resized_dir = p / "resized"
             resized_dir.mkdir(exist_ok=True)
             originals = [f for f in p.rglob("*") if is_image(f)]
-            print(f"resizing {len(originals)} image(s) in {p} → {resized_dir}")
+            logging.info(f"resizing {len(originals)} image(s) in {p} → {resized_dir}")
             for img in originals:
                 run_command(
                     [
                         "imgz",
                         "resize",
-                        "-o",
+                        "--output",
                         str(resized_dir / f"{img.stem}.resized.jpg"),
                         str(img),
                     ]
                 )
             if originals:
-                print(f"trashing {len(originals)} original(s)")
+                logging.info(f"trashing {len(originals)} original(s)")
                 move_to_trash(originals)
         else:
-            print(f"skipping {p}: already within size limits")
+            logging.info(f"skipping {p}: already within size limits")
 
         rename_children(p, flatten=True)
         remove_empty_dirs(p)
+        if archive_path is not None:
+            move_to_trash(file_paths=[archive_path])
 
 
 if __name__ == "__main__":
+    logging.basicConfig(level=logging.INFO, format="%(asctime)s %(levelname)s: %(message)s")
     cli()
diff --git a/download_imageset_test.py b/download_imageset_test.py
new file mode 100644
index 0000000..c22da76
--- /dev/null
+++ b/download_imageset_test.py
@@ -0,0 +1,86 @@
+#!/usr/bin/env -S uv run --script
+# /// script
+# requires-python = ">=3.11"
+# dependencies = ["pytest", "httpx", "pillow", "click"]
+# ///
+import sys
+import zipfile
+from pathlib import Path
+from unittest.mock import Mock
+
+import pytest
+from click.testing import CliRunner
+from PIL import Image
+
+import download_imageset
+
+
+@pytest.mark.parametrize("extension", [".zip", ".ZIP"])
+def test_process_zip_and_directory(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch, extension: str
+) -> None:
+    directory = tmp_path / "existing"
+    nested = directory / "nested"
+    nested.mkdir(parents=True)
+    image_path = nested / "photo.png"
+    Image.new(mode="RGB", size=(10, 10)).save(fp=image_path)
+    archive_path = tmp_path / f"gallery{extension}"
+    with zipfile.ZipFile(file=archive_path, mode="w") as archive:
+        archive.write(filename=image_path, arcname="album/photo.png")
+    trash = Mock()
+    monkeypatch.setattr(download_imageset, "move_to_trash", trash)
+
+    result = CliRunner().invoke(
+        cli=download_imageset.cli,
+        args=["process", str(archive_path), str(directory)],
+    )
+
+    assert result.exit_code == 0, result.output
+    assert (tmp_path / "gallery" / "gallery__0000.png").is_file()
+    assert (directory / "existing__0000.png").is_file()
+    assert not (tmp_path / "gallery" / "album").exists()
+    assert not nested.exists()
+    trash.assert_called_once_with(file_paths=[archive_path])
+
+
+@pytest.mark.parametrize("filename", ["missing", "unsupported.txt", "broken.zip"])
+def test_process_skips_invalid_inputs(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch, filename: str
+) -> None:
+    source = tmp_path / filename
+    if filename != "missing":
+        source.write_text(data="not an archive")
+    trash = Mock()
+    monkeypatch.setattr(download_imageset, "move_to_trash", trash)
+
+    result = CliRunner().invoke(
+        cli=download_imageset.cli, args=["process", str(source)]
+    )
+
+    assert result.exit_code == 0, result.output
+    trash.assert_not_called()
+    if filename != "missing":
+        assert source.read_text() == "not an archive"
+    assert not (tmp_path / "broken").exists()
+
+
+def test_process_keeps_zip_when_processing_fails(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    archive_path = tmp_path / "gallery.zip"
+    with zipfile.ZipFile(file=archive_path, mode="w") as archive:
+        archive.writestr(zinfo_or_arcname="photo.png", data=b"invalid image")
+    trash = Mock()
+    monkeypatch.setattr(download_imageset, "move_to_trash", trash)
+
+    result = CliRunner().invoke(
+        cli=download_imageset.cli, args=["process", str(archive_path)]
+    )
+
+    assert result.exit_code != 0
+    assert archive_path.is_file()
+    trash.assert_not_called()
+
+
+if __name__ == "__main__":
+    sys.exit(pytest.main(args=[str(Path(__file__).resolve()), *sys.argv[1:]]))