Run GUI program in bash without opening the window

Is it possible to run a GUI program and tell bash to not show the window? E.g. something like nogui firefox that runs Firefox but don't show the GUI window.

Let me explain my situation: I am processing some images with the program ds9. I have a bash script that opens an image in .fits format format with this program, then export it as .jpeg and then closes the program. It is working perfectly fine. However, each time I run this script, the GUI window of ds9 opens up, then exports the image and then closes. This is annoying when converting many images because there are windows opening an closing automatically for each image.