diff --git a/src/Helpers/MimeHelper.php b/src/Helpers/MimeHelper.php
index 5c538bdc..c1eaa4ed 100644
--- a/src/Helpers/MimeHelper.php
+++ b/src/Helpers/MimeHelper.php
@@ -17,17 +17,17 @@ class MimeHelper
 
 	public static function isFlash($mime)
 	{
-		return $mime === 'application/x-shockwave-flash';
+		return strtolower($mime) === 'application/x-shockwave-flash';
 	}
 
 	public static function isVideo($mime)
 	{
-		return $mime === 'application/ogg' or preg_match('/video\//', $mime);
+		return strtolower($mime) === 'application/ogg' or preg_match('/video\//i', $mime);
 	}
 
 	public static function isImage($mime)
 	{
-		return in_array($mime, ['image/jpeg', 'image/png', 'image/gif']);
+		return in_array(strtolower($mime), ['image/jpeg', 'image/png', 'image/gif']);
 	}
 
 	private static function stripCharset($mime)
diff --git a/tests/Helpers/MimeHelperTest.php b/tests/Helpers/MimeHelperTest.php
new file mode 100644
index 00000000..17285705
--- /dev/null
+++ b/tests/Helpers/MimeHelperTest.php
@@ -0,0 +1,39 @@
+<?php
+namespace Szurubooru\Tests\Helpers;
+
+class MimeHelperTest extends \Szurubooru\Tests\AbstractTestCase
+{
+	public function testGettingMime()
+	{
+		$expected = 'image/jpeg';
+		$actual = \Szurubooru\Helpers\MimeHelper::getMimeTypeFromBuffer($this->getTestFile('image.jpg'));
+		$this->assertEquals($expected, $actual);
+	}
+
+	public function testIsFlash()
+	{
+		$this->assertTrue(\Szurubooru\Helpers\MimeHelper::isFlash('application/x-shockwave-flash'));
+		$this->assertTrue(\Szurubooru\Helpers\MimeHelper::isFlash('APPLICATION/X-SHOCKWAVE-FLASH'));
+		$this->assertFalse(\Szurubooru\Helpers\MimeHelper::isFlash('something else'));
+	}
+
+	public function testIsImage()
+	{
+		$this->assertTrue(\Szurubooru\Helpers\MimeHelper::isImage('IMAGE/JPEG'));
+		$this->assertTrue(\Szurubooru\Helpers\MimeHelper::isImage('IMAGE/PNG'));
+		$this->assertTrue(\Szurubooru\Helpers\MimeHelper::isImage('IMAGE/GIF'));
+		$this->assertTrue(\Szurubooru\Helpers\MimeHelper::isImage('image/jpeg'));
+		$this->assertTrue(\Szurubooru\Helpers\MimeHelper::isImage('image/png'));
+		$this->assertTrue(\Szurubooru\Helpers\MimeHelper::isImage('image/gif'));
+		$this->assertFalse(\Szurubooru\Helpers\MimeHelper::isImage('something else'));
+	}
+
+	public function testIsVideo()
+	{
+		$this->assertTrue(\Szurubooru\Helpers\MimeHelper::isVideo('VIDEO/MP4'));
+		$this->assertTrue(\Szurubooru\Helpers\MimeHelper::isVideo('video/mp4'));
+		$this->assertTrue(\Szurubooru\Helpers\MimeHelper::isVideo('APPLICATION/OGG'));
+		$this->assertTrue(\Szurubooru\Helpers\MimeHelper::isVideo('application/ogg'));
+		$this->assertFalse(\Szurubooru\Helpers\MimeHelper::isVideo('something else'));
+	}
+}