add gamestate, doc and fix

core/photo_mode/photo_gallery.gd

@@ -0,0 +1,27 @@
+extends Control
+
+@onready var grid_container: GridContainer = $%PhotoGrid
+
+@onready var photo_scene = preload("res://core/photo_mode/photo.tscn")
+
+func _ready() -> void:
+	CollectionManager.on_photo_saved.connect(_create_photo_thumbnail)
+	load_gallery()
+
+func load_gallery() -> void:
+	for child in grid_container.get_children():
+		child.queue_free()
+		
+	var saved_photos = CollectionManager.saved_photos
+	
+	for file_path in saved_photos:
+		if FileAccess.file_exists(file_path):
+			_create_photo_thumbnail(file_path)
+
+func _create_photo_thumbnail(file_path: String) -> void:
+	var image = Image.load_from_file(file_path)
+	if image:
+		var photo: Photo = photo_scene.instantiate()
+		var texture = ImageTexture.create_from_image(image)
+		photo.setup(texture)
+		grid_container.add_child(photo)