diff --git a/cli/main.ts b/cli/main.ts
index d49556e..bf0b0cd 100644
--- a/cli/main.ts
+++ b/cli/main.ts
@@ -20,13 +20,17 @@ const args = parse(Deno.args, {
 });
 
 const files: string[] = [];
+const includeExtensions = Array.from(
+  String(args["include"] || "*.png, *.jpg").matchAll(/\*\.([\w]+)/g),
+).map(([_, group]) => group);
 
 args["_"].forEach((arg) => {
   arg = arg.toString();
   if (Deno.statSync(arg).isDirectory) {
-    Array.from(Deno.readDirSync(arg)).forEach((entry) =>
-      files.push(`${arg}/${entry.name}`)
-    );
+    Array.from(Deno.readDirSync(arg)).filter((entry) =>
+      includeExtensions.length == 0 ||
+      includeExtensions.some((ext) => entry.name.endsWith(ext))
+    ).forEach((entry) => files.push(`${arg}/${entry.name}`));
   } else {
     files.push(arg);
   }