Hi @Alireza_Fazeli - we currently do not support PNG export, though as @Hunter-Lanier noted there is no loss.
You may experience loss if you use our augmentations or preprocessing steps (particularly resizing). However, we encourage almost all users to resize down their images as the models perform well at small image sizes (e.g., 640x640) and you’ll get a noticeable throughput increase (which will save you GPU costs and make your applications run faster).