Okay, thank you all for your help with my other problems so far. Here is my last question for today:
I have a script that opens image files in Photoshop and creates thumbnails. If I do batch processing without a script, I can switch to a different program and the image processing continues in the background - this way I can use my computer while the batch processing is running, and it is also much faster, because, I guess, there is no rendering of large image files for the screen. But when I process the images by dragging a folder full of images on my script, the script brings Photoshop to the foreground each time it opens a new image, even if I switch to a different program - Photoshop simply comes to the front again. This makes the computer unusable for me during image processing, and it is much slower.
So, how can I force the script (or Photoshop) to work in the background? Or can I maybe even force them to work invisibly, like file renaming, which I don’t see at all, if I don’t open the image folder and look a the file names while they are being changed?