Is it possible to save RenderTextures into png files for later use?

Thanks for your help. I managed to capture a render texture, but it seems that it is only possible in OnRenderImage(). Is it possible to do it in other methods?

@AliAzin: you should be able to do it with Camera.Render.

here's some random example code, that may be of help to someone.

Starting at "RenderTexture tempRT = ..."

 public void MakeSquarePngFromOurVirtualThingy()
     {
     // capture the virtuCam and save it as a square PNG.
     
     int sqr = 512;
     
     virtuCamera.camera.aspect = 1.0f;
     // recall that the height is now the "actual" size from now on
     
     RenderTexture tempRT = new RenderTexture(sqr,sqr, 24 );
     // the 24 can be 0,16,24, formats like
     // RenderTextureFormat.Default, ARGB32 etc.
     
     virtuCamera.camera.targetTexture = tempRT;
     virtuCamera.camera.Render();
     
     RenderTexture.active = tempRT;
     Texture2D virtualPhoto =
         new Texture2D(sqr,sqr, TextureFormat.RGB24, false);
     // false, meaning no need for mipmaps
     virtualPhoto.ReadPixels( new Rect(0, 0, sqr,sqr), 0, 0);
     
     RenderTexture.active = null; //can help avoid errors 
     virtuCamera.camera.targetTexture = null;
     // consider ... Destroy(tempRT);
     
     byte[] bytes;
     bytes = virtualPhoto.EncodeToPNG();
     
     System.IO.File.WriteAllBytes(
         OurTempSquareImageLocation(), bytes );
     // virtualCam.SetActive(false); ... no great need for this.
     
     // now use the image, 
     UseFileImageAt( OurTempSquareImageLocation() );
     }
 
 private string OurTempSquareImageLocation()
     {
     string r = Application.persistentDataPath + "/p.png";
     return r;
     }