I am trying to write a python program that takes 10 pictures in a row and renames them as they are taken, but when I run the script, some of the pictures are missing. I end up getting Picture0, Picture1, Picture2, Picture4, Picture6, Picture7, Picture8, Picture9, or something of the like where a few numbers are skipped. I have successfully run the code once or twice where all the pictures came through, but most times, I end up with fewer pictures than I should.

indi_getprop -t 17 &
indi_setprop "SBIG CCD.CCD_EXPOSURE.CCD_EXPOSURE_VALUE=$1"
sleep 15
mv "SBIG CCD.CCD1.CCD1.fits" ~/mydirectory/"$2.fits"
sleep 2