diff --git a/wp-admin/includes/media.php b/wp-admin/includes/media.php
index 73a2585f84..5c0b5d0b38 100644
--- a/wp-admin/includes/media.php
+++ b/wp-admin/includes/media.php
@@ -2194,14 +2194,19 @@ function media_upload_form( $errors = null ) {
 		$plupload_init['multi_selection'] = false;
 	}
 
-	// Check if WebP images can be edited.
-	if ( ! wp_image_editor_supports( array( 'mime_type' => 'image/webp' ) ) ) {
-		$plupload_init['webp_upload_error'] = true;
-	}
+	/** This filter is documented in wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php */
+	$prevent_unsupported_uploads = apply_filters( 'wp_prevent_unsupported_mime_type_uploads', true, null );
 
-	// Check if AVIF images can be edited.
-	if ( ! wp_image_editor_supports( array( 'mime_type' => 'image/avif' ) ) ) {
-		$plupload_init['avif_upload_error'] = true;
+	if ( $prevent_unsupported_uploads ) {
+		// Check if WebP images can be edited.
+		if ( ! wp_image_editor_supports( array( 'mime_type' => 'image/webp' ) ) ) {
+			$plupload_init['webp_upload_error'] = true;
+		}
+
+		// Check if AVIF images can be edited.
+		if ( ! wp_image_editor_supports( array( 'mime_type' => 'image/avif' ) ) ) {
+			$plupload_init['avif_upload_error'] = true;
+		}
 	}
 
 	/**
diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
index 0c98a729e4..4c49a1f335 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
@@ -134,6 +134,36 @@ class WP_REST_Attachments_Controller extends WP_REST_Posts_Controller {
 				array( 'status' => rest_authorization_required_code() )
 			);
 		}
+		$files = $request->get_file_params();
+
+		/**
+		 * Filter whether the server should prevent uploads for image types it doesn't support. Default true.
+		 *
+		 * Developers can use this filter to enable uploads of certain image types. By default image types that are not
+		 * supported by the server are prevented from being uploaded.
+		 *
+		 * @since 6.8.0
+		 *
+		 * @param bool        $check_mime Whether to prevent uploads of unsupported image types.
+		 * @param string|null $mime_type  The mime type of the file being uploaded (if available).
+		 */
+		$prevent_unsupported_uploads = apply_filters( 'wp_prevent_unsupported_mime_type_uploads', true, isset( $files['file']['type'] ) ? $files['file']['type'] : null );
+
+		// If the upload is an image, check if the server can handle the mime type.
+		if (
+			$prevent_unsupported_uploads &&
+			isset( $files['file']['type'] ) &&
+			str_starts_with( $files['file']['type'], 'image/' )
+		) {
+			// Check if the image editor supports the type.
+			if ( ! wp_image_editor_supports( array( 'mime_type' => $files['file']['type'] ) ) ) {
+				return new WP_Error(
+					'rest_upload_image_type_not_supported',
+					__( 'The web server cannot generate responsive image sizes for this image. Convert it to JPEG or PNG before uploading.' ),
+					array( 'status' => 400 )
+				);
+			}
+		}
 
 		return true;
 	}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index acd44b97b4..e33f5b142b 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.8-beta3-60083';
+$wp_version = '6.8-beta3-60084';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.