diff --git a/cli/main.ts b/cli/main.ts
index 4113084..881a1b5 100644
--- a/cli/main.ts
+++ b/cli/main.ts
@@ -7,6 +7,7 @@ import DenoCollageModes, {
 } from "./collages.ts";
 import { CollageConfig } from "../src/common/types.ts";
 import { choice, shuffle } from "../src/common/utils.ts";
+import { walkSync } from "https://deno.land/std@0.107.0/fs/mod.ts";
 
 const canvasKit = await init();
 
@@ -16,7 +17,9 @@ const args = parse(Deno.args, {
     "h": "height",
     "o": "output",
     "m": "mode",
+    "r": "recursive",
   },
+  boolean: ["recursive"]
 });
 
 if (args["mode"] === true) {
@@ -24,7 +27,7 @@ if (args["mode"] === true) {
   Deno.exit(0);
 }
 
-const files: string[] = [];
+const files: Set<string> = new Set();
 const includeExtensions = Array.from(
   String(args["include"] || "*.png, *.jpg").matchAll(/\*\.([\w]+)/g),
 ).map(([_, group]) => group);
@@ -32,21 +35,27 @@ const includeExtensions = Array.from(
 args["_"].forEach((arg) => {
   arg = arg.toString();
   if (Deno.statSync(arg).isDirectory) {
-    Array.from(Deno.readDirSync(arg)).filter((entry) =>
-      includeExtensions.length == 0 ||
-      includeExtensions.some((ext) => entry.name.endsWith(ext))
-    ).forEach((entry) => files.push(`${arg}/${entry.name}`));
+    Array.from(
+      walkSync(arg, {
+        maxDepth: args["recursive"]
+          ? Infinity
+          : 1,
+        includeDirs: false,
+        includeFiles: true,
+        exts: includeExtensions.length ? includeExtensions : undefined,
+      }),
+    ).forEach((entry) => files.add(entry.path));
   } else {
-    files.push(arg);
+    files.add(arg);
   }
 });
 
-if (files.length < 2) {
+if (files.size < 2) {
   console.error("kollagen needs at least 2 images to work.");
   Deno.exit(1);
 }
 
-const shuffledFiles = shuffle(files);
+const shuffledFiles = shuffle(Array.from(files));
 
 if (shuffledFiles.length > 25) {
   console.debug(`Too many files available, shuffling and clamping to 25...`);
@@ -67,7 +76,7 @@ const mode = modes.modes[modeKey];
 console.log(
   `Creating a "${mode.name}" collage...`,
 );
-console.debug(`Images: ${files.join(", ")}`);
+console.debug(`Images: ${shuffledFiles.join(", ")}`);
 
 const canvas = createCanvas(args["width"] || 640, args["height"] || 640);
 const context = canvas.getContext("2d");