stop it from redownloading already cached files (or pages but i guess you could use the function for anything)

src/cache.rs

@@ -1,9 +1,13 @@
-use std::{fs, process};
+use std::{fs, process, path::Path};
 
 pub async fn download_image(cache_path: &str, image_url: String, file_name: String) {
     let replaced = cache_path.replace('~', &crate::get_home()[..]); // replace ~ with $HOME
     crate::ensure_exists(&replaced);
 
+    if Path::new(&format!("{cache_path}/{file_name}")).exists() {
+        return
+    }
+
     let image = match reqwest::get(image_url).await {
         Ok(image) => match image.bytes().await {
             Ok(bytes) => bytes,