--- src-tauri/src/main.rs
+++ src-tauri/src/main.rs
@@ -40,40 +40,42 @@
 }

 #[tauri::command]
-fn write_text_file(app: AppHandle, contents: String, is_sum: bool) -> Result<(), String> {
+fn write_text_file(app: AppHandle, contents: String, is_sum: bool) -> Result<bool, String> {
     let (name, ext) = if is_sum {
         ("Summarum Sheet", "sum")
     } else {
         ("Text file", "txt")
     };
     if let Some(p) = app
         .dialog()
         .file()
         .add_filter(name, &[ext])
         .blocking_save_file()
     {
         write_atomic(&p.into_path().map_err(|e| e.to_string())?, &contents)?;
+        Ok(true)
+    } else {
+        Ok(false)
     }
-    Ok(())
 }

 #[tauri::command]
-fn write_image_file(app: AppHandle, data_base64: String) -> Result<(), String> {
+fn write_image_file(app: AppHandle, data_base64: String) -> Result<bool, String> {
     if let Some(p) = app
         .dialog()
         .file()
         .add_filter("PNG Image", &["png"])
         .blocking_save_file()
     {
         let path = p.into_path().map_err(|e| e.to_string())?;
         use std::io::Write;
         let bytes = base64_decode(&data_base64)?;
         let tmp = path.with_extension("tmp");
         std::fs::File::create(&tmp)
             .and_then(|mut f| f.write_all(&bytes))
             .map_err(|e| e.to_string())?;
         fs::rename(&tmp, path).map_err(|e| e.to_string())?;
+        Ok(true)
+    } else {
+        Ok(false)
     }
-    Ok(())
 }

 fn base64_decode(s: &str) -> Result<Vec<u8>, String> {