Automatically generate screenshots for all examples (#2379)

examples/retained_image/Cargo.toml

@@ -9,6 +9,8 @@ publish = false
 
 
 [dependencies]
-eframe = { path = "../../crates/eframe" }
+eframe = { path = "../../crates/eframe", features = [
+    "__screenshot", # __screenshot is so we can dump a ascreenshot using EFRAME_SCREENSHOT_TO
+] }
 egui_extras = { path = "../../crates/egui_extras", features = ["image"] }
 image = { version = "0.24", default-features = false, features = ["png"] }

examples/retained_image/README.md

@@ -1,3 +1,7 @@
+Example how to show an image with eframe/egui.
+
 ```sh
 cargo run -p retained_image
 ```
+
+![](screenshot.png)

examples/retained_image/src/main.rs

@@ -5,7 +5,7 @@ use egui_extras::RetainedImage;
 
 fn main() {
     let options = eframe::NativeOptions {
-        initial_window_size: Some(egui::vec2(500.0, 900.0)),
+        initial_window_size: Some(egui::vec2(300.0, 900.0)),
         ..Default::default()
     };