try to decode the image header as soon as some data is available

src/node_image.h

@@ -21,6 +21,7 @@ public:
     uint16_t m_tex_id;
     std::shared_ptr<Asset> m_remote_asset;
     std::shared_ptr<Texture2D> m_remote_texture;
+    bool m_remote_header_decoded = false;
     static void static_init();
     virtual Node* clone_instantiate() const override;
     virtual void clone_copy(Node* dest) const override;