Change command line args

pdfpreview and pdf to image field just died on me. Both use imagemagick to convert pds to images. The culprit looks like it is the latest version of ghostscript 9.26

https://stackoverflow.com/questions/53560755/ghostscript-9-26-update-bre...
https://stackoverflow.com/questions/53560755/ghostscript-9-26-update-bre...

My errors are of the form:

pdf_to_image_shell_exec did not create image /sites/default/files/connections/3076-0.jpg as expected. convert: FailedToExecuteCommand `'gs' -q -dQUIET -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=2 '-sDEVICE=pngalpha' -dTextAlphaBits=4 -dGraphicsAlphaBits=4 '-r25x25' -dFirstPage=1 -dLastPage=1 '-sOutputFile=/tmp/magick-39385HkU0XCPG0hsC%d' '-f/tmp/magick-39385Pegsl8Qkx1nN' '-f/tmp/magick-39385YcbEcnTbXOjY'' (-1) @ error/delegate.c/ExternalDelegateCommand/462. convert: no images defined `/sites/default/files/connections/3076-0.jpg' @ error/convert.c/ConvertImageCommand/3257.

According to the above links, removing -dFirstPage=1 -dLastPage=1 and possibly -dMaxBitmap=500000000 from the command line provides a workaround. Due to our current hosting situation I cannot just roll back to an earlier version of ghostcript (which was working in Aug/Sep).

So, my question is can the above command line be changed any where?

Thanks