diff --git a/script.js b/script.js
index 5a5c15d..fe320e1 100644
--- a/script.js
+++ b/script.js
@@ -1,5 +1,7 @@
 dropzone = document.getElementById('dropzone');
 
+filetypes = ['image/png', 'image/jpeg', 'image/gif'];
+
 dropzone.addEventListener('dragover', function(e) {
 	e.preventDefault();
 	this.classList.remove('inactive');
@@ -28,7 +30,7 @@ dropzone.addEventListener('click', function(e) {
 
 	input.onchange = function(e) {
 		file = e.target.files[0];
-		if(file.type == 'image/png' || file.type == 'image/jpeg' || file.type == 'image/gif') {
+		if(filetypes.includes(file.type)) {
 			upload(e.target.files[0]);
 		}
 	}
@@ -41,7 +43,7 @@ dropzone.addEventListener('drop', function(e) {
 	this.classList.add('inactive');
 	
 	file = e.dataTransfer.files[0];
-	if(file.type == 'image/png' || file.type == 'image/jpeg' || file.type == 'image/gif') {
+	if(filetypes.includes(file.type)) {
 		upload(e.dataTransfer.files[0]);
 	}
 });
diff --git a/upload.php b/upload.php
index ebf3a9b..df78ad2 100644
--- a/upload.php
+++ b/upload.php
@@ -10,11 +10,13 @@ if(!is_dir($datadir)) {
 	mkdir($datadir);
 }
 
+$extensions = ['jpg', 'jpeg', 'png', 'gif'];
+
 if(isset($_FILES['upload'])) {
 	$extension = pathinfo($_FILES['upload']['name'], PATHINFO_EXTENSION);
 	$extension = strtolower($extension);
 
-	if($extension == 'jpg' || $extension == 'jpeg' || $extension == 'png' || $extension == 'gif') {
+	if(in_array($extension, $extensions)) {
 		$filename = generate_filename($length) . '.' . $extension;
 		move_uploaded_file($_FILES['upload']['tmp_name'], $datadir . '/' . $filename);
 		echo json_encode(['datadir' => $datadir, 'filename' => $filename]);