diff --git a/readme.txt b/readme.txt
index efcd949..9bd6b02 100644
--- a/readme.txt
+++ b/readme.txt
@@ -4,7 +4,7 @@ Donate link: https://tinypng.com/
 Tags: compress images, compression, image size, page speed, performance
 Requires at least: 4.0
 Tested up to: 6.8
-Stable tag: 3.6.2
+Stable tag: 3.6.3
 License: GPLv2 or later
 License URI: http://www.gnu.org/licenses/gpl-2.0.html
 
@@ -174,6 +174,9 @@ A: You can upgrade to a paid account by adding your *Payment details* on your [a
 A: When the conversion feature is enabled (to convert images to AVIF or WebP), each image will use double the number of credits: one for compression and one for format conversion.
 
 == Changelog ==
+= 3.6.3 =
+* Changed the source priority for picture elements
+
 = 3.6.2 =
 * Resolved an issue where the amount of parameters were incorrect when rendering a notice.
 
diff --git a/src/class-tiny-picture.php b/src/class-tiny-picture.php
index 0d2de81..fbb05ea 100644
--- a/src/class-tiny-picture.php
+++ b/src/class-tiny-picture.php
@@ -198,7 +198,7 @@ public function __construct( $html, $base_dir, $domains ) {
 		$this->raw_html 	   = $html;
 		$this->base_dir        = $base_dir;
 		$this->allowed_domains = $domains;
-		$this->valid_mimetypes = array( 'image/webp', 'image/avif' );
+		$this->valid_mimetypes = array( 'image/avif', 'image/webp' );
 	}
 
 	protected static function get_attribute_value( $element, $name ) {
@@ -405,15 +405,12 @@ class Tiny_Picture_Source extends Tiny_Source_Base {
 	public function augment_picture_element() {
 		$modified_sources = array();
 
-		// handle existing sources
-		$optimized_types = [ 'image/webp', 'image/avif' ];
-
 		foreach ( $this->get_element_by_tag( $this->raw_html, 'source' ) as $source_tag_html ) {
 			$type_attr = self::get_attribute_value( $source_tag_html, 'type' );
 			$type_attr = null !== $type_attr ? strtolower( trim( $type_attr ) ) : '';
 
 			// Skip if already optimized.
-			if ( '' !== $type_attr && in_array( $type_attr, $optimized_types, true ) ) {
+			if ( '' !== $type_attr && in_array( $type_attr, $this->valid_mimetypes, true ) ) {
 				continue;
 			}
 
diff --git a/src/class-tiny-plugin.php b/src/class-tiny-plugin.php
index ce6f839..1dd7f73 100644
--- a/src/class-tiny-plugin.php
+++ b/src/class-tiny-plugin.php
@@ -18,7 +18,7 @@
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 class Tiny_Plugin extends Tiny_WP_Base {
-	const VERSION = '3.6.0';
+	const VERSION = '3.6.3';
 	const MEDIA_COLUMN = self::NAME;
 	const DATETIME_FORMAT = 'Y-m-d G:i:s';
 
diff --git a/test/unit/TinyPictureTest.php b/test/unit/TinyPictureTest.php
index 056c258..c974e07 100644
--- a/test/unit/TinyPictureTest.php
+++ b/test/unit/TinyPictureTest.php
@@ -199,7 +199,7 @@ public function test_adds_both_avif_and_webp()
         $this->wp->createImage(1000, '2025/01', 'test.avif');
 
         $input = '<img src="/wp-content/uploads/2025/01/test.png">';
-        $expected = '<picture><source srcset="/wp-content/uploads/2025/01/test.webp" type="image/webp" /><source srcset="/wp-content/uploads/2025/01/test.avif" type="image/avif" /><img src="/wp-content/uploads/2025/01/test.png"></picture>';
+        $expected = '<picture><source srcset="/wp-content/uploads/2025/01/test.avif" type="image/avif" /><source srcset="/wp-content/uploads/2025/01/test.webp" type="image/webp" /><img src="/wp-content/uploads/2025/01/test.png"></picture>';
         $output = $this->tiny_picture->replace_sources($input);
 
         $this->assertEquals($expected, $output);
diff --git a/tiny-compress-images.php b/tiny-compress-images.php
index 55a264a..3b4bb6f 100644
--- a/tiny-compress-images.php
+++ b/tiny-compress-images.php
@@ -2,7 +2,7 @@
 /**
  * Plugin Name: TinyPNG - JPEG, PNG & WebP image compression
  * Description: Speed up your website. Optimize your JPEG, PNG, and WebP images automatically with TinyPNG.
- * Version: 3.6.2
+ * Version: 3.6.3
  * Author: TinyPNG
  * Author URI: https://tinypng.com
  * Text Domain: tiny-compress-images