diff --git a/.gitignore b/.gitignore
index 9691e1e..ced2395 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 node_modules
 .venv
 dist
+images
 
 # Python
 __pycache__
@@ -8,4 +9,4 @@ __pycache__
 
 src/ipyniivue/static
 
-launch.json
\ No newline at end of file
+launch.json
diff --git a/README.md b/README.md
index d462fef..78a93f7 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ anywidget.
 pip install ipyniivue
 ```
 
-# Usage
+## Usage
 
 In a Jupyter environment:
 
@@ -23,7 +23,7 @@ nv
 
 See the [basic demo](./demo/basic_multiplanar.ipynb) to learn more.
 
-# Development
+## Development
 
 **ipyniivue** uses [the
 recommended](https://packaging.python.org/en/latest/flow/#) `hatchling`
diff --git a/demo/additive_voxels.ipynb b/demo/additive_voxels.ipynb
index 7261d2d..8e9f5a4 100644
--- a/demo/additive_voxels.ipynb
+++ b/demo/additive_voxels.ipynb
@@ -6,6 +6,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "!mkdir -p ../images/\n",
     "!wget https://github.com/niivue/niivue/raw/main/demos/images/narps-4735_50GV-hypo1_unthresh.nii.gz -P ../images/\n",
     "!wget https://github.com/niivue/niivue/raw/main/demos/images/narps-4965_9U7M-hypo1_unthresh.nii.gz -P ../images/\n",
     "!wget https://github.com/niivue/niivue/raw/main/demos/images/mni152.nii.gz -P ../images/"
@@ -59,13 +60,6 @@
     "ipywidgets.link((sgreen, \"value\"), (nv.volumes[2], \"cal_min\"))\n",
     "ipywidgets.HBox([sred, sgreen])"
    ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": []
   }
  ],
  "metadata": {
@@ -84,7 +78,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.12.1"
+   "version": "3.12.2"
   },
   "widgets": {
    "application/vnd.jupyter.widget-state+json": {
diff --git a/demo/basic_multiplanar.ipynb b/demo/basic_multiplanar.ipynb
index 16d2baf..9bc1412 100644
--- a/demo/basic_multiplanar.ipynb
+++ b/demo/basic_multiplanar.ipynb
@@ -1,5 +1,16 @@
 {
  "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "!mkdir -p ../images/\n",
+    "!wget https://github.com/niivue/niivue/raw/main/demos/images/mni152.nii.gz -P ../images/\n",
+    "!wget https://github.com/niivue/niivue/raw/main/demos/images/hippo.nii.gz -P ../images/"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -26,7 +37,7 @@
    "outputs": [],
    "source": [
     "nv.volumes[0].opacity = 0.3\n",
-    "nv.volumes[1].colormap = \"blue\"\n"
+    "nv.volumes[1].colormap = \"blue\""
    ]
   },
   {
@@ -40,13 +51,13 @@
     "nv.back_color = [1,1,1,1]\n",
     "nv.clip_plane_color =  [0,1,1,1]\n",
     "nv.is_colorbar = True\n",
-    "nv.view_mode_hot_key = \"KeyN\"\n"
+    "nv.view_mode_hot_key = \"KeyN\""
    ]
   }
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": ".venv",
+   "display_name": "Python 3 (ipykernel)",
    "language": "python",
    "name": "python3"
   },
@@ -60,9 +71,16 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.11.7"
+   "version": "3.12.2"
+  },
+  "widgets": {
+   "application/vnd.jupyter.widget-state+json": {
+    "state": {},
+    "version_major": 2,
+    "version_minor": 0
+   }
   }
  },
  "nbformat": 4,
- "nbformat_minor": 2
+ "nbformat_minor": 4
 }
diff --git a/images/hippo.nii.gz b/images/hippo.nii.gz
deleted file mode 100644
index 971b839..0000000
Binary files a/images/hippo.nii.gz and /dev/null differ