refactor export equirectangular

src/image.h

@@ -11,13 +11,14 @@ public:
     bool load_file(std::string filename);
     const uint8_t* data() const { return m_data.get(); }
     int size() const { return width * height * comp; }
-    bool save(const std::string& path);
-    void create(int w, int h) 
+    bool save_png(const std::string& path);
+    bool save_jpg(const std::string& path, int quality);
+    void create(int w, int h, uint8_t* data = nullptr)
     { 
         width = w; 
         height = h;  
         comp = 4;
-        m_data = std::make_unique<uint8_t[]>(size());
+        m_data = data ? std::unique_ptr<uint8_t[]>(data) : std::make_unique<uint8_t[]>(size());
     }
     void copy_from(const uint8_t* data)
     {