diff --git a/constants/data.js b/constants/data.js
new file mode 100644
index 00000000..52d69977
--- /dev/null
+++ b/constants/data.js
@@ -0,0 +1,5 @@
+
+export const
+  _1KB = 1024,
+  _1MB = _1KB * _1KB,
+  _1GB = _1KB * _1MB;
diff --git a/src/components/generators/StoryboardComponent.jsx b/src/components/generators/StoryboardComponent.jsx
index 74d75eb6..11c67ccf 100644
--- a/src/components/generators/StoryboardComponent.jsx
+++ b/src/components/generators/StoryboardComponent.jsx
@@ -1,23 +1,18 @@
-import {useState, useEffect} from 'react';
+import { useState, useEffect } from 'react';
 import classnames from 'classnames';
 
-import {PlaceholderImg} from '../placeholders/PlaceholderImg.jsx';
-import {ArrayBufferRenderer} from '../renderers/ArrayBufferRenderer.jsx';
-// import {zbencode, zbdecode} from '../../zine/encoding.js';
-import {downloadFile} from '../../utils/http-utils.js';
+import { PlaceholderImg } from '../placeholders/PlaceholderImg.jsx';
+import { ArrayBufferRenderer } from '../renderers/ArrayBufferRenderer.jsx';
 import styles from '../../../styles/Storyboard.module.css';
-import {
-  zineMagicBytes,
-} from '../../zine/zine-format.js';
-import {
-  mainImageKey,
-} from '../../zine/zine-data-specs.js';
+import { zineMagicBytes } from '../../zine/zine-format.js';
+import { mainImageKey } from '../../zine/zine-data-specs.js';
+import { decompressStream } from '../../utils/compression.js';
+import { loadStream, saveCompressedStream } from '../../utils/file/index.js'
 
-//
 
 const textDecoder = new TextDecoder();
+const defaultFilename = 'storyboard.zine.gz';
 
-//
 
 const StoryboardPanel = ({
   storyboard,
@@ -151,21 +146,24 @@ export const StoryboardComponent = ({
       onDrop={drop}
     >
       <div className={styles.buttons}>
-        <button className={styles.button} onClick={e => {
+        <button className={styles.button} onClick={async e => {
           e.preventDefault();
           e.stopPropagation();
 
-          const uint8Array = storyboard.export();
-          // const firstBytes = uint8Array.slice(0, 4);
-          // const firstBytesString = textDecoder.decode(firstBytes);
-          // console.log('export decoded', {firstBytesString});
-          const blob = new Blob([
-            zineMagicBytes,
-            uint8Array,
-          ], {
-            type: 'application/octet-stream',
-          });
-          downloadFile(blob, 'storyboard.zine');
+          // Export the storyboard to a blob.
+          const
+            uint8Array = storyboard.export(),
+
+            blob = new Blob([
+              zineMagicBytes,
+              uint8Array,
+            ], {
+              type: 'application/octet-stream',
+            });
+
+          // Compress and stream blob to file.
+          // TODO: Estimate compressed size so we can show progress.
+          await saveCompressedStream(blob.stream(), defaultFilename);
         }}>
           <img src='/images/download.svg' className={styles.img} />
         </button>
@@ -175,7 +173,17 @@ export const StoryboardComponent = ({
             const file = e.target.files[0];
             if (file) {
               (async () => {
-                const arrayBuffer = await file.arrayBuffer();
+                const
+                  // Decompress stream.
+                  // TODO: Estimate compressed size so we can show progress.
+                  stream = loadStream(
+                    decompressStream(file.stream()),
+                    file.name
+                  ),
+
+                  // Get array buffer.
+                  arrayBuffer = await new Response( stream ).arrayBuffer();
+
                 // check magic bytes
                 const firstBytes = new Uint8Array(arrayBuffer, 0, 4);
                 const firstBytesString = textDecoder.decode(firstBytes);
@@ -212,4 +220,4 @@ export const StoryboardComponent = ({
       />
     </div>
   )
-};
\ No newline at end of file
+};
diff --git a/src/utils/compression.js b/src/utils/compression.js
new file mode 100644
index 00000000..159ca770
--- /dev/null
+++ b/src/utils/compression.js
@@ -0,0 +1,22 @@
+
+
+/**
+ * Compress a blob and return a readable stream.
+ * @param {ReadableStream<any>} stream The stream to compress.
+ * @returns {ReadableStream<any>} The compressed stream.
+ */
+export function compressStream(stream) {
+  //noinspection JSUnresolvedFunction
+  return stream.pipeThrough(new CompressionStream('gzip'));
+}
+
+
+/**
+ * Decompress a blob and return a readable stream.
+ * @param {ReadableStream<any>} stream The stream to decompress.
+ * @returns {ReadableStream<any>} The decompressed stream.
+ */
+export function decompressStream(stream) {
+  //noinspection JSUnresolvedFunction
+  return stream.pipeThrough(new DecompressionStream('gzip'));
+}
diff --git a/src/utils/file/index.js b/src/utils/file/index.js
new file mode 100644
index 00000000..b88904e8
--- /dev/null
+++ b/src/utils/file/index.js
@@ -0,0 +1,5 @@
+
+export { loadStream } from './loadStream.js';
+export { pipeResponseToFile } from './pipeResponseToFile.js';
+export { saveCompressedStream } from './saveCompressedStream.js';
+export { saveStream } from './saveStream.js';
diff --git a/src/utils/file/loadStream.js b/src/utils/file/loadStream.js
new file mode 100644
index 00000000..18b4b11f
--- /dev/null
+++ b/src/utils/file/loadStream.js
@@ -0,0 +1,18 @@
+import { UploadToast } from '../toasts/index.js'
+
+
+/**
+ * Load a stream.
+ * @param {ReadableStream<any>} stream The stream to load.
+ * @param {string} name The name of the stream.
+ * @param {number} [size] The total size of the stream.
+ * @returns {ReadableStream<any>} The stream.
+ */
+export function loadStream(
+  stream = new ReadableStream(),
+  name = 'stream',
+  size,
+) {
+  return stream
+    .pipeThrough(new UploadToast(name, size).pipe);
+}
diff --git a/src/utils/file/pipeResponseToFile.js b/src/utils/file/pipeResponseToFile.js
new file mode 100644
index 00000000..fa45077b
--- /dev/null
+++ b/src/utils/file/pipeResponseToFile.js
@@ -0,0 +1,23 @@
+import { DownloadToast } from '../toasts/index.js'
+
+
+/**
+ * Pipe a response to a file.
+ * @param {Response} response The response to pipe.
+ * @param {FileSystemFileHandle} handle The file handle.
+ * @param {number} [size] The total size of the response.
+ * @returns {Promise<FileSystemFileHandle>} The file handle.
+ */
+export async function pipeResponseToFile(response, handle, size) {
+  //noinspection JSUnresolvedFunction
+  const writable = await handle.createWritable();
+
+  // Notify the user that the download has begun.
+  const toast = new DownloadToast(handle.name, size);
+
+  await response.body
+    .pipeThrough(toast.pipe)
+    .pipeTo(writable)
+
+  return handle;
+}
diff --git a/src/utils/file/saveCompressedStream.js b/src/utils/file/saveCompressedStream.js
new file mode 100644
index 00000000..b8f49998
--- /dev/null
+++ b/src/utils/file/saveCompressedStream.js
@@ -0,0 +1,22 @@
+import { compressStream } from '../compression.js'
+import { saveStream } from './saveStream.js'
+
+
+const gzipTypes = [{
+  description: 'Gzip',
+  accept: {
+    'application/gzip': ['.gz'],
+  }
+}]
+
+
+/**
+ * Compresses a stream and save it to a file.
+ * @param {ReadableStream<any>} stream The stream to compress.
+ * @param {string} suggestedName The suggested name.
+ * @param {number} [size] The total size of the stream.
+ * @returns {Promise<FileSystemFileHandle>} The file handle.
+ */
+export function saveCompressedStream(stream, suggestedName, size) {
+  return saveStream(compressStream(stream), gzipTypes, suggestedName, size);
+}
diff --git a/src/utils/file/saveStream.js b/src/utils/file/saveStream.js
new file mode 100644
index 00000000..5cd49190
--- /dev/null
+++ b/src/utils/file/saveStream.js
@@ -0,0 +1,40 @@
+import { pipeResponseToFile } from './pipeResponseToFile.js';
+
+
+const defaultTypes = [{
+  description: 'File',
+  accept: {
+    'application/octet-stream': ['.bin'],
+  }
+}];
+
+
+/**
+ * Get the first file extension from a types object.
+ */
+function getFirstExtension(types) {
+  return Object.values(types[0].accept)[0][0];
+}
+
+
+/**
+ * Save a stream to a file.
+ * @param {ReadableStream<any>} stream The blob to save.
+ * @param {Array<object>} types The file types.blob
+ * @param {string} suggestedName The suggested filename.
+ * @param {number} [size] The total size of the stream.
+ * @returns {Promise<FileSystemFileHandle>} The file handle.
+ */
+export async function saveStream(
+  stream = new ReadableStream(),
+  types = defaultTypes,
+  suggestedName = `file${getFirstExtension(types)}`,
+  size,
+) {
+  // Prepare a response and get a file handle.
+  //noinspection JSUnresolvedFunction
+  const handle = await window.showSaveFilePicker({ types, suggestedName });
+
+  await pipeResponseToFile(new Response(stream), handle, size);
+  return handle;
+}
diff --git a/src/utils/http-utils.js b/src/utils/http-utils.js
index 0a369a82..bfd9be93 100644
--- a/src/utils/http-utils.js
+++ b/src/utils/http-utils.js
@@ -1,3 +1,4 @@
+
 export const getFormData = o => {
   const formData = new FormData();
   for (const k in o) {
@@ -16,4 +17,4 @@ export function downloadFile(file, filename) {
   document.body.appendChild(tempLink);
   tempLink.click();
   document.body.removeChild(tempLink);
-}
\ No newline at end of file
+}
diff --git a/src/utils/toasts/DownloadToast.js b/src/utils/toasts/DownloadToast.js
new file mode 100644
index 00000000..8ce839f1
--- /dev/null
+++ b/src/utils/toasts/DownloadToast.js
@@ -0,0 +1,106 @@
+import { _1MB } from '../../../constants/data.js';
+
+import {
+  backgroundColor,
+  failColor,
+  successColor,
+  toastDuration
+} from './constants.js';
+
+import { Toast } from './Toast.js';
+
+
+const
+  /**
+   * Notify the user and remove the toast if the download fails.
+   */
+  handleError = (ctx, e) => {
+    // Notify the user.
+    ctx.toast.textContent =
+      `Download failed for ${ctx.name}: ${e.message}`;
+
+    // Change bg color and remove after a delay.
+    ctx.toast.style.background = failColor;
+    setTimeout(() => ctx.remove(), toastDuration);
+  };
+
+  
+/**
+ * A toast which tracks the progress of a streamed download.
+ */
+export class DownloadToast extends Toast {
+  currentSize = 0;
+  name = '';
+  loaded = 0;
+
+  pipe = createPipe( this )
+  size;
+  
+  /**
+   * Create a new download toast.
+   * @param {string} [name] The stream's name.
+   * @param {number} [size] The stream's total size.
+   */
+  constructor( name= '', size ) {
+    super();
+
+    // Set name and size.
+    this.name = name;
+    if (size) this.size = (size / _1MB).toFixed(2);
+
+    // Set initial text.
+    this.toast.textContent = `Downloading ${this.name}... (0MB)`;
+  }
+}
+
+
+const createPipe = ctx => {
+  return new TransformStream({
+    /**
+     * Update the toast as the download progresses.
+     * @param {Uint8Array} chunk The chunk of data.
+     * @param {TransformStreamDefaultController} controller The controller.
+     */
+    transform: (chunk, controller) => {
+      // TransformStream.transform doesn't catch errors by default.
+      try {
+        // Update metrics.
+        ctx.loaded += chunk.length;
+        ctx.currentSize = (ctx.loaded / _1MB ).toFixed(2);
+
+        // Show current progress.
+        if ( ctx.size || ctx.size === 0 )  {
+          // Update text.
+          ctx.toast.textContent =
+            `Downloading ${ctx.name}... ` +
+            `(${ctx.currentSize}/${ctx.size} MB)`;
+
+          // Update progress bar.
+          ctx.toast.style.background =
+            `linear-gradient(to right, ` +
+            `${successColor} ${ctx.currentSize / ctx.size * 100}%, ` +
+            `${backgroundColor} ${ctx.currentSize / ctx.size * 100}%)`;
+        } else {
+          ctx.toast.textContent =
+            `Downloading ${ctx.name}... (${ctx.currentSize} MB)`;
+        }
+        
+        // Continue.
+        controller.enqueue(chunk);
+      } catch (e) { handleError(ctx, e); }
+    },
+
+    /**
+     * Remove the toast when the download is complete.
+     */
+    flush: () => {
+      // Notify the user.
+      ctx.toast.textContent =
+        `Downloaded ${ctx.name}. (${ctx.currentSize} MB)`;
+
+      // Change bg color and remove after a delay.
+      ctx.toast.style.background = successColor;
+      setTimeout(() => ctx.remove(), toastDuration);
+    },
+  })
+}
diff --git a/src/utils/toasts/Toast.js b/src/utils/toasts/Toast.js
new file mode 100644
index 00000000..c299a564
--- /dev/null
+++ b/src/utils/toasts/Toast.js
@@ -0,0 +1,37 @@
+import { backgroundColor } from './constants.js';
+
+
+const toastStyle =
+  'position: fixed;' +
+  'bottom: 0;' +
+  'left: 0;' +
+  'right: 0;' +
+  `background: ${backgroundColor};` +
+  'color: #fff;' +
+  'padding: 16px;' +
+  'text-align: center;';
+
+
+/**
+ * Creates a toast element for displaying messages to the user.
+ */
+export class Toast {
+  // Toast element
+  toast = null;
+
+  /**
+   * Create a new toast.
+   */
+  constructor() {
+    // Create, format and append a toast element.
+    this.toast = document.createElement('div');
+    this.toast.style = toastStyle;
+
+    document.body.appendChild(this.toast);
+  }
+
+  /**
+   * Remove the toast.
+   */
+  remove() { this.toast.remove(); }
+}
diff --git a/src/utils/toasts/UploadToast.js b/src/utils/toasts/UploadToast.js
new file mode 100644
index 00000000..ff4d541b
--- /dev/null
+++ b/src/utils/toasts/UploadToast.js
@@ -0,0 +1,104 @@
+import { _1MB } from '../../../constants/data.js';
+
+import {
+  backgroundColor,
+  failColor,
+  successColor,
+  toastDuration
+} from './constants.js';
+
+import { Toast } from './Toast.js';
+
+
+const
+  /**
+   * Notify the user and remove the toast if the download fails.
+   */
+  handleError = (ctx, e) => {
+    // Notify the user.
+    ctx.toast.textContent =
+      `Upload failed for ${ctx.name}: ${e.message}`;
+
+    // Change bg color and remove after a delay.
+    ctx.toast.style.background = failColor;
+    setTimeout(() => ctx.remove(), toastDuration);
+  };
+
+/**
+ * A toast which tracks the progress of a streamed download.
+ */
+export class UploadToast extends Toast {
+  currentSize = 0;
+  name = '';
+  loaded = 0;
+
+  pipe = createPipe( this )
+  size;
+  
+  /**
+   * Create a new download toast.
+   * @param {string} name The stream's name.
+   * @param {number} [size] The stream's total size.
+   */
+  constructor( name = '', size) {
+    super();
+
+    // Set name and size.
+    this.name = name;
+    if (size) this.size = (size / _1MB).toFixed(2);
+
+    // Set initial text.
+    this.toast.textContent = `Uploading ${this.name}... (0MB)`;
+  }
+}
+
+
+const createPipe = ctx => {
+  return new TransformStream({
+    /**
+     * Update the toast as the download progresses.
+     * @param {Uint8Array} chunk The chunk of data.
+     * @param {TransformStreamDefaultController} controller The controller.
+     */
+    transform: (chunk, controller) => {
+      // TransformStream.transform doesn't catch errors by default.
+      try {
+        // Update metrics.
+        ctx.loaded += chunk.length;
+        ctx.currentSize = (ctx.loaded / _1MB ).toFixed(2);
+
+        // Show current progress.
+        if ( ctx.size || ctx.size === 0 )  {
+          ctx.toast.textContent =
+            `Uploading ${ctx.name}... ` +
+            `(${ctx.currentSize}/${ctx.size} MB)`;
+
+          // Update progress bar.
+          ctx.toast.style.background =
+            `linear-gradient(to right, ` +
+            `${successColor} ${ctx.currentSize / ctx.size * 100}%, ` +
+            `${backgroundColor} ${ctx.currentSize / ctx.size * 100}%)`;
+        } else {
+          ctx.toast.textContent =
+            `Uploading ${ctx.name}... (${ctx.currentSize} MB)`;
+        }
+        
+        // Continue.
+        controller.enqueue(chunk);
+      } catch (e) { handleError(ctx, e); }
+    },
+
+    /**
+     * Remove the toast when the download is complete.
+     */
+    flush: () => {
+      // Notify the user.
+      ctx.toast.textContent =
+        `Uploaded ${ctx.name}. (${ctx.currentSize} MB)`;
+
+      // Change bg color and remove after a delay.
+      ctx.toast.style.background = successColor;
+      setTimeout(() => ctx.remove(), toastDuration);
+    },
+  })
+}
diff --git a/src/utils/toasts/constants.js b/src/utils/toasts/constants.js
new file mode 100644
index 00000000..ccbba67b
--- /dev/null
+++ b/src/utils/toasts/constants.js
@@ -0,0 +1,6 @@
+
+export const
+  backgroundColor = '#333',
+  failColor = 'firebrick',
+  successColor = 'forestgreen',
+  toastDuration = 5000;
diff --git a/src/utils/toasts/index.js b/src/utils/toasts/index.js
new file mode 100644
index 00000000..6a2b0453
--- /dev/null
+++ b/src/utils/toasts/index.js
@@ -0,0 +1,4 @@
+
+export { DownloadToast } from './DownloadToast.js';
+export { Toast } from './Toast.js';
+export { UploadToast } from './UploadToast.js';
diff --git a/styles/Storyboard3DRenderer.module.css b/styles/Storyboard3DRenderer.module.css
index 16d7c67d..a3cdcaeb 100644
--- a/styles/Storyboard3DRenderer.module.css
+++ b/styles/Storyboard3DRenderer.module.css
@@ -39,6 +39,7 @@
 
 .storyboard3DRenderer .layers {
   display: flex;
+  overflow-x: auto;
 }
 .storyboard3DRenderer .layers .layer {
   width: 150px;
@@ -56,4 +57,4 @@
 }
 .storyboard3DRenderer .layers .layer.selected {
   cursor: default;
-}
\ No newline at end of file
+}