Model: rely on draining image data

src/main.rs

@@ -34,6 +34,5 @@ fn main() {
     // export saved image data
     println!("Rendering all saved image data....");
     model.render_all_imgdata();
-    model.flush_image_data();
     println!("Done!");
 }

src/model.rs

@@ -159,14 +159,9 @@ impl Model {
                 self.img_data_vec.len()
             );
             self.render_all_imgdata();
-            self.flush_image_data();
         }
     }
 
-    pub fn flush_image_data(&mut self) {
-        self.img_data_vec.clear();
-    }
-
     pub fn render_all_imgdata(&mut self) {
         if !Path::new("./tmp").exists() {
             std::fs::create_dir("./tmp").expect("could create directory");