diff --git a/WXGFDecoder/README.md b/WXGFDecoder/README.md
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--- /dev/null
+++ b/WXGFDecoder/README.md
@@ -0,0 +1,27 @@
+
+# WXGF Decoder
+
+This is an android app that decodes wechat's proprietary "WXGF/WXAM" image format.
+
+
+## Build & Install
+
+Open this project directory using android studio, and build against an ARMv8 device.
+
+Pre-built APKs can be downloaded at [releases](https://github.com/ppwwyyxx/wechat-dump/releases).
+
+Install the APK to your android phone.
+
+Note that this app uses native libs, therefore requires an ARMv8 compatible device to run.
+The native libs are extracted from the WeChat v7.0.22 APK downloaded from [here](https://www.apkmirror.com/apk/wechat-tencent/wechat/wechat-7-0-22-release/wechat-7-0-22-android-apk-download/)
+
+## Use
+
+![image](screenshot.jpg)
+
+1. (Optional) Configure the port number if needed, or leave it to default.
+2. Click "Start Server"
+3. Use the server address `ws://xx.xx.xx.xx:xxxx` to decode
+   * Make sure this address is accessible from the computer that runs `wechat-dump`.
+     For example, connect them into the same Wifi.
+4. Once a client is connected and decoding request is received, logs will be printed in the app.
diff --git a/WXGFDecoder/screenshot.jpg b/WXGFDecoder/screenshot.jpg
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diff --git a/dump-html.py b/dump-html.py
index bb02bfd..7cc8a65 100755
--- a/dump-html.py
+++ b/dump-html.py
@@ -15,9 +15,10 @@ logger = logging.getLogger("wechat")
 def get_args():
     parser = argparse.ArgumentParser()
     parser.add_argument('name', help='name of contact')
-    parser.add_argument('--output', help='output html file', default='output.html')
-    parser.add_argument('--db', default='decoded.db', help='path to decoded database')
-    parser.add_argument('--res', default='resource', help='reseource directory')
+    parser.add_argument('--output', help='output html file, e.g. output.html', default='output.html')
+    parser.add_argument('--db', default='EnMicroMsg.db.decoded',
+                        help='path to the decoded database, e.g. EnMicroMsg.db.decoded')
+    parser.add_argument('--res', default='resource', help='the resource directory')
     parser.add_argument('--wxgf-server', help='address of the wxgf image decoder server')
     parser.add_argument('--avt', default='avatar.index', help='path to avatar.index file that only exists in old version of wechat. Ignore for new version of wechat.')
     args = parser.parse_args()