Hi every one, , not how to rescale an object.

i need to know how to obtain the size of an object in pixels, something like gameobject cube 234x123 pixels may be it is easy but i dont know how to do it, i need a script to get the size in pixels of a cube or a botton preferably, and show it in the unity console, it is because i need to know the measures of the textures i need to put in the box or button so that the texture looks good and not to pixeled. i found here some code like this:

  [MenuItem("Window/ShowSize")]
 static void Init()
 {
     // Get existing open window or if none, make a new one:
     ShowSize sizeWindow = new ShowSize();
     sizeWindow.autoRepaintOnSceneChange = true;
     sizeWindow.Show();
 }
 
 void OnGUI () {
     GameObject thisObject = Selection.activeObject as GameObject;
     if (thisObject == null)
     {
         return;
     }
     
     MeshFilter mf = thisObject.GetComponent(typeof(MeshFilter)) as MeshFilter;
     if (mf == null)
     {return;}
     
     Mesh mesh = mf.sharedMesh;
     if (mesh == null)      
     {return;}
     
     Vector3 size = mesh.bounds.size;
     Vector3 scale = thisObject.transform.localScale;
     GUILayout.Label("Size\nX: " + size.x*scale.x + "   Y: " + size.y*scale.y + "   Z:              " + size.z*scale.z);
 }

but this just give me the scale of the object in a show size windows, and that doesn't work for me. thanks a lot by the way, im new in unity3d edition =)