diff --git a/src/image.cpp b/src/image.cpp
index 244b9aa..3bdf2a3 100644
--- a/src/image.cpp
+++ b/src/image.cpp
@@ -102,7 +102,7 @@ bool Image::save(const std::string &filename)
     unsigned error = lodepng::encode(filename, pixels, width, height, colorType, 8);
     if(error)
         fprintf(stderr, lodepng_error_text(error));
-    return error != 0;
+    return error == 0;
 }
 
 bool Image::save(std::vector<unsigned char> &out)
@@ -212,7 +212,7 @@ void TexturePack::destroyGL()
 	}
 }
 
-TexturePack::TexturePack(const std::string &folderPath) : TexturePack()
+bool TexturePack::load(const std::string &folderPath)
 {
 	m_name = getNameFromFilename(folderPath);
 	tinydir_dir dir;
@@ -220,12 +220,17 @@ TexturePack::TexturePack(const std::string &folderPath) : TexturePack()
 	if(err == -1)
 	{
 		fprintf(stderr, "can't open directory : \"%s\"\n", folderPath.c_str());
-		return;
+		return false;
 	}
-	int n = dir.n_files;
-	for(int i=0; i<n; ++i)
+	while(dir.has_next)
 	{
-		const tinydir_file &file = dir._files[i];
+		tinydir_file file;
+        tinydir_readfile(&dir, &file);
+        if(std::string(file.name) == "." || std::string(file.name) == ".." || file.is_dir)
+        {
+            tinydir_next(&dir);
+            continue;
+        }
 		if(std::string(file.extension) == "png")
 		{
 			Image* img = new Image(std::string(file.path));
@@ -234,20 +239,26 @@ TexturePack::TexturePack(const std::string &folderPath) : TexturePack()
 		}
 		else
 			fprintf(stderr, "%s is not a png file, ignoring\n", file.path);
+        tinydir_next(&dir);
 	}
+	return true;
 }
 
 bool TexturePack::save(const std::string &folderPath)
 {
 	std::string path = folderPath + '/' + m_name;
-	if(!tinydir_create_directory(path.c_str()))
-	{
-        fprintf(stderr, "can't create directory \"%s\"\n", path.c_str());
-        return false;
-	}
 	tinydir_dir dir;
 	int err = tinydir_open(&dir, path.c_str());
 	if(err == -1)
+	{
+        if(!tinydir_create_directory(path.c_str()))
+        {
+            fprintf(stderr, "can't create directory \"%s\"\n", path.c_str());
+            return false;
+        }
+	}
+	err = tinydir_open(&dir, path.c_str());
+	if(err == -1)
 	{
 		fprintf(stderr, "can't open directory : \"%s\"\n", path.c_str());
 		return false;
@@ -258,7 +269,7 @@ bool TexturePack::save(const std::string &folderPath)
         TexImage &texImg = pair.second;
         if(texImg.img != NULL)
         {
-            std::string filename = path + '/' + texImg.name + ".png";
+            std::string filename = path + '/' + texImg.name;
             if(!texImg.img->save(filename))
                 fprintf(stderr, "can't save image : \"%s\"\n", filename.c_str());
         }
diff --git a/src/image.h b/src/image.h
index 635bbfd..17ae9d5 100644
--- a/src/image.h
+++ b/src/image.h
@@ -110,7 +110,7 @@ public:
      * every png file in the folder will be loaded in the pack
      * and named from the file name minus its extension
      */
-    TexturePack(const std::string &folderPath);
+    bool load(const std::string &folderPath);
     
     /**
      * @brief saves the texture pack as png images in the specified existing folder
diff --git a/src/model.cpp b/src/model.cpp
index 3f30fb0..f9429ad 100644
--- a/src/model.cpp
+++ b/src/model.cpp
@@ -8,7 +8,7 @@ Model::Model() : m_texPack(NULL) {}
 
 Model::~Model()
 {
-    destroy();
+    initDestroy();
     destroyGL();
     for(Mesh *m : m_meshes)
         delete m;
@@ -22,22 +22,29 @@ void Model::setTexturePack(TexturePack *texPack)
     m_texPack = texPack;
 }
 
-void Model::destroy()
+void Model::initDestroy()
 {
+    initGL();
     for(Mesh* m : m_meshes)
         m->clearData();
+    if(m_texPack != NULL)
+        m_texPack->initDestroyImages();
 }
 
 void Model::initGL()
 {
     for(Mesh* m : m_meshes)
         m->initGL();
+    if(m_texPack != NULL)
+        m_texPack->initGL();
 }
 
 void Model::destroyGL()
 {
     for(Mesh* m : m_meshes)
         m->destroyGL();
+    if(m_texPack != NULL)
+        m_texPack->destroyGL();
 }
 
 bool Model::save(const std::string &filename, const std::string &texturesPath)
@@ -47,11 +54,11 @@ bool Model::save(const std::string &filename, const std::string &texturesPath)
     if(file == NULL)
         return false;
     
+    // write meshes and materials, there is no material sharing (1 mesh = 1 material)
     bool ok = false;
     int size = m_meshes.size();
     if(std::fwrite(&size, sizeof(int), 1, file))
-    {   
-        // write meshes and materials, there is no material sharing (1 mesh = 1 material)
+    {
         ok = true;
         for(Mesh* m : m_meshes)
         {
@@ -59,19 +66,13 @@ bool Model::save(const std::string &filename, const std::string &texturesPath)
             PhongMaterial* mat = (PhongMaterial*)m->getMaterial();
             ok = ok && mat->serialize(file);
         }
-        // write texture pack
-        
-        /*for(Model::TextureImg &texImg : m_textures)
-        {
-            std::string texFilename = texturesPath + texImg.name + ".png";
-            if(texImg.img == NULL && texImg.tex != NULL)
-                texImg.img = texImg.tex->getData();
-            if(texImg.img != NULL)
-                ok = ok && texImg.img->save(texFilename);
-        }*/
         std::fclose(file);
     }
     
+    // saves the TexturePack
+    if(m_texPack != NULL)
+        ok = ok && m_texPack->save(texturesPath);
+    
     // finishing
     return ok;
 }
@@ -86,6 +87,7 @@ Model* Model::load(const std::string &filename, const std::string &texturesPath)
     bool ok = false;
     
     
+    
     // finishing
     return NULL;
 }
diff --git a/src/model.h b/src/model.h
index 89e4455..c51c4a8 100644
--- a/src/model.h
+++ b/src/model.h
@@ -42,10 +42,11 @@ public:
     //Texture* getTexture(const std::string &name);
     
     /**
-     * @brief destroy frees Mesh and Image memory in the RAM, but it stays allocated in GPU memory.
-     * (not supported yet when rendering because of flags)
+     * @brief uploads meshes and images to GPU memory,
+     * then frees Mesh and Image memory in the RAM,
+     * so it stays allocated only in GPU memory.
      */
-    void destroy();
+    void initDestroy();
     
     /**
      * @brief initGL uploads image and mesh data to GPU memory
diff --git a/src/phongmaterial.cpp b/src/phongmaterial.cpp
index 4ef2b7e..aa10f48 100644
--- a/src/phongmaterial.cpp
+++ b/src/phongmaterial.cpp
@@ -95,6 +95,8 @@ bool PhongMaterial::serialize(PhongMaterial* mat, FILE *file)
         {
             if(mat->textures[i] != NULL)
                 header.textureLengths[i] = mat->textureNames[i].length()+1;
+            else
+                header.textureLengths[i] = 0;
         }
         
         if(!std::fwrite(&header, sizeof(MaterialHeader), 1, file))