diff --git a/public/index/constants.js b/public/index/constants.js
index b2a6970..b53b92a 100644
--- a/public/index/constants.js
+++ b/public/index/constants.js
@@ -17,6 +17,22 @@
 
 /** @type {SupportedFileType[]} */
 export const SUPPORTED_FILE_TYPES = [
+  {
+    name: "GIF",
+    extensions: [".gif", "image/gif"],
+    mimeType: "image/gif",
+    route: "/gif",
+    mimeSniffPatterns: [
+      {
+        bytes: [0x47, 0x49, 0x46, 0x38, 0x37, 0x61],
+        mask: [0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF],
+      },
+      {
+        bytes: [0x47, 0x49, 0x46, 0x38, 0x39, 0x61],
+        mask: [0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF],
+      },
+    ],
+  },
   {
     name: "PNG",
     extensions: [".png", ".apng"],
diff --git a/public/index/index.js b/public/index/index.js
index 0c24bc2..410a0bd 100644
--- a/public/index/index.js
+++ b/public/index/index.js
@@ -17,13 +17,24 @@ const inputEl = /** @type {HTMLInputElement} */ (
 );
 const inputContainerEl = crel("p", {}, inputEl);
 
-const supportedFileTypeNameString = SUPPORTED_FILE_TYPES
-  .map((t, index, array) => (
-    (array.length > 1 && (index === array.length - 1))
-      ? `and ${t.name}`
-      : t.name
-  ))
-  .join(", ");
+const supportedFileTypeNameString = (() => {
+  switch (SUPPORTED_FILE_TYPES.length) {
+    case 0:
+      return "no";
+    case 2:
+      return `${SUPPORTED_FILE_TYPES[0].name} and ${
+        SUPPORTED_FILE_TYPES[1].name
+      }`;
+    default:
+      return SUPPORTED_FILE_TYPES
+        .map((t, index, array) => (
+          (array.length > 1 && (index === array.length - 1))
+            ? `and ${t.name}`
+            : t.name
+        ))
+        .join(", ");
+  }
+})();
 const labelParagraphEl = crel(
   "p",
   {},
diff --git a/test/index/routeFile.test.ts b/test/index/routeFile.test.ts
index de1612f..b49a47a 100644
--- a/test/index/routeFile.test.ts
+++ b/test/index/routeFile.test.ts
@@ -2,13 +2,30 @@ import { assertEquals } from "assert";
 import routeFile from "../../public/index/routeFile.js";
 
 Deno.test("routes files correctly", async () => {
-  const PNG_SIGNATURE = new Uint8Array([137, 80, 78, 71, 13, 10, 26, 10]);
+  const PNG_SIGNATURE = new Uint8Array([
+    0x89,
+    0x50,
+    0x4E,
+    0x47,
+    0x0D,
+    0x0A,
+    0x1A,
+    0x0A,
+  ]);
+  const GIF87_SIGNATURE = new Uint8Array([0x47, 0x49, 0x46, 0x38, 0x37, 0x61]);
+  const GIF89_SIGNATURE = new Uint8Array([0x47, 0x49, 0x46, 0x38, 0x39, 0x61]);
 
   const testCases = new Map<File, null | string>([
     // No matching type
     [new File([], "foo"), null],
     [new File([], "foo.txt"), null],
     [new File([], "foo.txt", { type: "text/plain" }), null],
+    // GIF
+    [new File([], "foo", { type: "image/gif" }), "/gif"],
+    [new File([], "foo.gif"), "/gif"],
+    [new File([], "foo.gif", { type: "text/plain" }), "/gif"],
+    [new File([GIF87_SIGNATURE], "foo"), "/gif"],
+    [new File([GIF89_SIGNATURE], "foo"), "/gif"],
     // PNG
     [new File([], "foo", { type: "image/png" }), "/png"],
     [new File([], "foo.png"), "/png"],