Copy the images into the output.

src/context/dependency_manager.rs

@@ -58,4 +58,11 @@ impl DependencyManager {
         });
         Ok(())
     }
+
+    /// Return the dependencies and forget about them.
+    pub(crate) fn take_dependencies(&mut self) -> Vec<Dependency> {
+        let mut dependencies = Vec::new();
+        std::mem::swap(&mut self.dependencies, &mut dependencies);
+        dependencies
+    }
 }