window: Dont take width and height in window constructor

Always set this by scheduling an initial resize.
diff --git a/clients/image.c b/clients/image.c
index 7ffe20a..8f621eb 100644
--- a/clients/image.c
+++ b/clients/image.c
@@ -205,7 +205,7 @@
 
 	image->filename = g_strdup(filename);
 
-	image->window = window_create(display, 500, 400);
+	image->window = window_create(display);
 	image->widget = frame_create(image->window, image);
 	window_set_title(image->window, title);
 	image->display = display;