diff --git a/web/src/harmonie/Harmonie.tsx b/web/src/harmonie/Harmonie.tsx
index f444a9b..1212b5d 100644
--- a/web/src/harmonie/Harmonie.tsx
+++ b/web/src/harmonie/Harmonie.tsx
@@ -90,6 +90,7 @@ export const Harmonie: Component<{}> = () => {
         </div>
         <div class={styles.column}>
             <SlideShow
+                getIsLoading={getIsLoading}
                 getCanvas={getCanvas}
                 getImgList={getImgList}
             />
diff --git a/web/src/harmonie/SlideShow.tsx b/web/src/harmonie/SlideShow.tsx
index 0283b83..8e3be9d 100644
--- a/web/src/harmonie/SlideShow.tsx
+++ b/web/src/harmonie/SlideShow.tsx
@@ -1,32 +1,89 @@
-import { Accessor, Component } from 'solid-js'
+import { Accessor, Component, createSignal } from 'solid-js'
 
 import styles from './harmonie.module.css'
+import { downloadImagesAsZip } from '../helpers/download'
 
 export const SlideShow: Component<{
+    getIsLoading: Accessor<boolean>,
     getCanvas: Accessor<HTMLCanvasElement | undefined>,
     getImgList: Accessor<[string, ImageBitmap | undefined][]>,
 }> = ({
+    getIsLoading,
     getCanvas,
     getImgList
 }) => {
-    function draw(img: ImageBitmap | undefined) {
+    const [getActive, setActive] = createSignal(-1)
+    const [getIsPlaying, setIsPlaying] = createSignal(false)
+
+    function draw(i: number) {
         const canvas = getCanvas()!
         const ctx = canvas.getContext('2d')!
         ctx.clearRect(0, 0, canvas.width, canvas.height)
+        setActive(i)
+        const img = getImgList()[i][1]
         if (!img) return;
 
         ctx.drawImage(img, 0, 0)
     }
 
-    return <ul class={styles.slideShow}>
-        { getImgList().map(([forecastDate, img]) =>
-        <li class={img ? styles.withImg : ''} onClick={() => draw(img)}>
-            { format(forecastDate) }
-        </li>)}
-    </ul>
+    function next(delta = 1) {
+        const count = getImgList().length
+        if (!count) return;
+
+        const result = (getActive() + delta) % count
+        const nextValue = result >= 0 ? result : count - 1
+        setActive(nextValue)
+        draw(nextValue)
+    }
+
+    function prev() { next(-1) }
+
+    function areControlsVisible(): boolean {
+        return getImgList().length > 0 && !getIsLoading()
+    }
+
+    let playingTimeout = 0
+    function play() {
+        if (getIsPlaying()) {
+            clearTimeout(playingTimeout)
+            setIsPlaying(false)
+            return;
+        }
+
+        function loop() {
+            next()
+            playingTimeout = setTimeout(loop, 300)
+        }
+        setIsPlaying(true)
+        loop()
+    }
+
+    function download() {
+        const imgs = getImgList().filter(([,img]) => !!img) as [string, ImageBitmap][]
+        downloadImagesAsZip(imgs)
+    }
+
+    return <>
+        <div class={styles.slideShowControls} style={{visibility: areControlsVisible() ? 'visible' : 'hidden'}}>
+            <div class={styles.leftButtons}>
+                <input type='button' value='prev' onClick={prev} />
+                <input type='button' value={getIsPlaying()?'pause':'play'} onClick={play} />
+                <input type='button' value='next' onClick={() => next()} />
+            </div>
+            <input type='button' value='download all' onClick={download} />
+        </div>
+        <ul class={styles.slideShowList}>
+            { getImgList().map(([forecastDate, img], i) =>
+            <li
+                class={`${img?styles.withImg:''} ${i===getActive()?styles.active:''}`}
+                onClick={() => draw(i)}
+            >
+                { format(forecastDate) }
+            </li>)}
+        </ul>
+    </>
 }
 
 function format(date: string) {
-    return date.slice(11, 13)
-    // return date
+    return date.slice(11, 13) // 2025-02-23T1500Z -> 15
 }
\ No newline at end of file
diff --git a/web/src/harmonie/harmonie.module.css b/web/src/harmonie/harmonie.module.css
index bb2c8e1..d2a6fb4 100644
--- a/web/src/harmonie/harmonie.module.css
+++ b/web/src/harmonie/harmonie.module.css
@@ -70,17 +70,34 @@
     padding: 10px 3px;
 }
 
-.slideShow {
+
+
+.slideShowControls {
+    display: flex;
+    justify-content: space-between;
+}
+
+.slideShowControls .leftButtons {
+    display: flex;
+    gap: 5px;
+}
+
+.slideShowList {
     padding: 0;
 }
 
-.slideShow li {
+.slideShowList li {
     display: inline;
     font-size: 14px;
-    padding: 3px 3px;
+    padding: 3px 1px;
     border-radius: 5px;
+    border: 2px solid transparent;
 }
 
 .withImg {
-    background-color: rgb(187, 247, 187);
+    background-color: rgb(213, 248, 213);
+}
+
+.slideShowList li.active {
+    border: 2px solid green;
 }
\ No newline at end of file
diff --git a/web/src/helpers/download.ts b/web/src/helpers/download.ts
new file mode 100644
index 0000000..0daeca8
--- /dev/null
+++ b/web/src/helpers/download.ts
@@ -0,0 +1,46 @@
+export async function downloadImagesAsZip(images: [string, ImageBitmap][]) {
+    downloadCompressedImage(images[0][1], '00.gzip')
+}
+
+async function compressImage(bitmap: ImageBitmap): Promise<Blob> {
+    // First convert ImageBitmap to WebP using canvas
+    const canvas = document.createElement('canvas');
+    canvas.width = bitmap.width;
+    canvas.height = bitmap.height;
+    
+    const ctx = canvas.getContext('2d');
+    if (!ctx) throw new Error('Could not get canvas context');
+    
+    ctx.drawImage(bitmap, 0, 0);
+    
+    // Get WebP blob
+    const webpBlob = await new Promise<Blob>((resolve) => {
+      canvas.toBlob((blob) => {
+        if (blob) resolve(blob);
+      }, 'image/webp', 0.8); // Quality 0.8, adjust as needed
+    });
+  
+    // Convert Blob to ReadableStream
+    const webpStream = webpBlob.stream();
+    
+    // Apply GZIP compression
+    const compressedStream = webpStream.pipeThrough(
+      new CompressionStream('gzip')
+    );
+  
+    // Return as Blob
+    return new Response(compressedStream).blob();
+  }
+  
+  // Usage example:
+  async function downloadCompressedImage(bitmap: ImageBitmap, filename: string) {
+    const compressedBlob = await compressImage(bitmap);
+    
+    const url = URL.createObjectURL(compressedBlob);
+    const link = document.createElement('a');
+    link.href = url;
+    link.download = filename;
+    link.click();
+    
+    URL.revokeObjectURL(url);
+  }
\ No newline at end of file