diff --git a/src/handlers/proxy.rs b/src/handlers/proxy.rs
index 0b188ab..b1bd6dd 100644
--- a/src/handlers/proxy.rs
+++ b/src/handlers/proxy.rs
@@ -21,9 +21,9 @@ pub async fn proxy_handler(
 
     // парсим GET запрос
     let (base_filename, requested_width, extension) = parse_image_request(&normalized_path);
-
-    let filekey = format!("{}.{}", base_filename, extension);
-    let content_type = match extension.as_str() {
+    let ext = extension.to_lowercase();
+    let filekey = format!("{}.{}", base_filename, &ext);
+    let content_type = match ext.as_str() {
         "jpg" | "jpeg" => "image/jpeg",
         "png" => "image/png",
         "webp" => "image/webp",
@@ -54,7 +54,7 @@ pub async fn proxy_handler(
                             // find closest thumb width
                             let closest: u32 = find_closest_width(requested_width as u32);
                             let thumb_filename =
-                                &format!("{}_{}.{}", base_filename, closest, extension);
+                                &format!("{}_{}.{}", base_filename, closest, ext);
 
                             return match check_file_exists(
                                 &state.storj_client,
@@ -164,9 +164,9 @@ async fn thumbdata_save(
     if content_type.starts_with("image") {
         warn!("original file name: {}", original_filename);
         let (base_filename, _, extension) = parse_image_request(&original_filename);
-        let filename = format!("{}.{}", base_filename, extension);
-
-        warn!("file extension: {}", extension);
+        warn!("detected file extension: {}", extension);
+        let ext = extension.to_lowercase();
+        let filename = format!("{}.{}", base_filename, ext);
 
         let img = match image::load_from_memory(&original_data) {
             Ok(img) => img,
@@ -180,7 +180,7 @@ async fn thumbdata_save(
             match generate_thumbnails(&img).await {
                 Ok(thumbnails_bytes) => {
                     for (thumb_width, thumbnail) in thumbnails_bytes {
-                        let thumb_filename = format!("{}_{}.{}", base_filename, thumb_width, extension);
+                        let thumb_filename = format!("{}_{}.{}", base_filename, thumb_width, ext);
                         // Загружаем миниатюру в S3
                         if let Err(e) = upload_to_s3(
                             &state.storj_client,