Opencart already comes with a really useful image manager but these changes help to make it, even more, user-friendly.

1. Auto sanitize filename by removing spaces and other unrecognized symbols and characters.
2. Auto rename if the file already exists. E.g image.jpg, image_2.jpg image_3,jpg, etc
3. Fix orientation. If you upload directly via mobile camera this can sometimes be wrong. This modification will try to fix this automatically as you upload. 
   Reference: https://forum.opencart.com/viewtopic.php?t=171530