Finally I decide to streamline my upload workflow. I have been using sitecopy for months but I was always manually picking files for upload before running it. I decided that it takes too much time. Script modifications allow me to run in from task scheduler at 1AM.
1. Pick 10 random files from my ready images (no repetitions from series should happen)
2. Upload with sitecopy to all the sites in the list
3. Move uploaded images to backup location (I am thinking about putting backup on Amazon S3)
In the morning it does not take long to submit 10 images on every site.