diff --git a/src/main.rs b/src/main.rs
index 5b794af..53e7ac9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -234,7 +234,11 @@ impl State {
 
         match path.extension().map(OsStr::to_string_lossy).as_deref() {
             Some("jxl") => {
-                let mut encoder = jpegxl_rs::encoder_builder().build().unwrap();
+                let mut encoder = jpegxl_rs::encoder_builder()
+                    .speed(jpegxl_rs::encode::EncoderSpeed::Glacier)
+                    .lossless(true)
+                    .build()
+                    .unwrap();
                 let rgb_image = DynamicImage::from(image.to_owned()).into_rgb8();
                 let jxl = match encoder.encode::<u8, u8>(
                     &rgb_image,