diff --git a/islands/ImagesCompressor.tsx b/islands/ImagesCompressor.tsx
index a80c3e8..2d8e846 100644
--- a/islands/ImagesCompressor.tsx
+++ b/islands/ImagesCompressor.tsx
@@ -8,6 +8,7 @@ import {
   startCompressing,
   updateCompressionOptions,
 } from "@/signals/home.ts";
+import { CompressionOptions } from "@/lib/compress.ts";
 
 function IdleSection() {
   const compressionOptions = getCompressionOptions();
@@ -55,12 +56,30 @@ function IdleSection() {
       disabled: getSelectedImages().length <= 1,
     },
   }, {
-    name: "convertToJpeg",
-    label: "convert to JPEG",
-    inputCheckbox: {
-      checked: compressionOptions.convertToJpeg,
-      onChange: (value: boolean) =>
-        updateCompressionOptions({ convertToJpeg: value }),
+    name: "convert",
+    label: "convert to",
+    select: {
+      onChange: (value: CompressionOptions["convert"]) =>
+        updateCompressionOptions({ convert: value }),
+      options: [
+        {
+          value: "none",
+          children: "none",
+        },
+        {
+          value: "image/jpeg",
+          children: "jpg",
+        },
+        {
+          value: "image/png",
+          children: "png",
+        },
+        {
+          value: "image/webp",
+          children: "webp",
+        },
+      ],
+      value: compressionOptions.convert,
     },
   }];
 
@@ -69,7 +88,7 @@ function IdleSection() {
       <details className="cursor-pointer my-6 px-4 select-none">
         <summary className="mb-4">Settings</summary>
         {settingsInputs.map(
-          ({ name, label, inputRange, inputNumber, inputCheckbox }) => (
+          ({ name, label, inputRange, inputNumber, inputCheckbox, select }) => (
             <div className="flex flex-wrap align-center justify-center gap-4 my-4">
               <label for={name}>{label}</label>
               <div className="flex flex-nowrap align-center justify-center gap-4 text-slate-950">
@@ -112,6 +131,20 @@ function IdleSection() {
                       )}
                   />
                 )}
+                {select && (
+                  <select
+                    className="px-2"
+                    onChange={(ev) =>
+                      select.onChange(
+                        (ev.target as HTMLSelectElement)
+                          .value as CompressionOptions["convert"],
+                      )}
+                  >
+                    {select.options.map((opt) => (
+                      <option value={opt.value}>{opt.children}</option>
+                    ))}
+                  </select>
+                )}
               </div>
             </div>
           ),
diff --git a/lib/compress.ts b/lib/compress.ts
index bb5b97a..3fdbe86 100644
--- a/lib/compress.ts
+++ b/lib/compress.ts
@@ -7,7 +7,7 @@ export interface CompressionOptions {
   maxHeight: number;
   zipFile: boolean;
   hardwareConcurrency: number;
-  convertToJpeg: boolean;
+  convert: "image/png" | "image/jpeg" | "image/webp" | "none";
 }
 
 interface WorkerCompressOptions {
@@ -34,8 +34,8 @@ export async function compress(
   const zipWriter = new ZipWriter(zipFileWriter);
 
   for (const file of imageFiles) {
-    const filename = options.convertToJpeg
-      ? replaceExtension(file.name, "jpg")
+    const filename = options.convert !== "none"
+      ? replaceExtension(file.name, fileTypeToExtension[options.convert])
       : file.name;
 
     const p = (async () => {
@@ -63,7 +63,7 @@ export async function compress(
       } else {
         // Download images directly.
         const blob = new Blob([compressedImg], {
-          type: options.convertToJpeg ? "image/jpeg" : file.type,
+          type: options.convert !== "none" ? options.convert : file.type,
         });
         downloadBlob(blob, filename);
       }
@@ -83,6 +83,12 @@ export async function compress(
   return results;
 }
 
+const fileTypeToExtension = {
+  "image/png": "png",
+  "image/jpeg": "jpg",
+  "image/webp": "jpg",
+};
+
 function downloadBlob(blob: Blob, filename: string) {
   const anchor = document.createElement("a");
   anchor.href = window.URL.createObjectURL(blob);
@@ -94,7 +100,7 @@ function replaceExtension(filename: string, ext: string) {
   const splitted = filename.split(".");
   if (splitted.length === 1) {
     splitted.push(ext);
-  } else if (splitted[splitted.length - 1].toLowerCase() !== "jpg") {
+  } else if (splitted[splitted.length - 1].toLowerCase() !== ext) {
     splitted[splitted.length - 1] = ext;
   }
 
diff --git a/signals/home.ts b/signals/home.ts
index 83edd03..187683c 100644
--- a/signals/home.ts
+++ b/signals/home.ts
@@ -22,7 +22,7 @@ const defaultCompressionOptions: CompressionOptions = {
   maxHeight: 4096,
   zipFile: true,
   hardwareConcurrency: (navigator.hardwareConcurrency ?? 8) / 4,
-  convertToJpeg: true,
+  convert: "none",
 };
 
 const compressionOptions = signal<CompressionOptions>({
diff --git a/static/worker_script.js b/static/worker_script.js
index f65b375..f69a927 100644
--- a/static/worker_script.js
+++ b/static/worker_script.js
@@ -39,11 +39,20 @@ function workerProcedureHandler(
   };
 }
 
+function isLosslessImageFormat(format) {
+  switch (format) {
+    case "image/webp", "image/jpeg":
+      return false;
+    default:
+      return true;
+  }
+}
+
 self.onmessage = workerProcedureHandler({
   setupWorker(workedId) {
     console.debug("worker", workedId, "setup");
   },
-  async compress(imageFile, { quality, maxWidth, maxHeight, convertToJpeg }) {
+  async compress(imageFile, { quality, maxWidth, maxHeight, convert }) {
     let bitmap = await createImageBitmap(imageFile);
     let drawWidth = bitmap.width;
     let drawHeight = bitmap.height;
@@ -67,11 +76,13 @@ self.onmessage = workerProcedureHandler({
 
     ctx.clearRect(0, 0, offscreenCanvas.width, offscreenCanvas.height);
 
-    // Image is not a JPEG images, apply JPEG encoding to compress it.
-    if (imageFile.type !== "image/jpeg" && !convertToJpeg) {
+    const convertToLossless = isLosslessImageFormat(
+      convert !== "none" ? convert : imageFile.type,
+    );
+    if (convertToLossless) {
       ctx.drawImage(bitmap, 0, 0, drawWidth, drawHeight);
       const blob = await offscreenCanvas.convertToBlob({
-        type: "image/jpeg",
+        type: "image/webp",
         quality: quality / 100,
       });
 
@@ -81,8 +92,8 @@ self.onmessage = workerProcedureHandler({
     ctx.drawImage(bitmap, 0, 0, drawWidth, drawHeight);
 
     const blob = await offscreenCanvas.convertToBlob({
-      type: convertToJpeg ? "image/jpeg" : imageFile.type,
-      quality: quality / 100,
+      type: convert === "none" ? imageFile.type : convert,
+      quality: convertToLossless ? undefined : quality / 100,
     });
 
     return blob.arrayBuffer();