[gradsusr] Cannot output in jpg or gif

[jason at solargrafix.com]

Hello,

I am trying to output an image to a format other than png.  I can create 
the png without any problem, but I can not create gif or jpg.  If I 
change the file extension to gif or jpg in my script, nothing is 
created.

Here is the line in my script I am using to create the image...

'printim C:\xampp\htdocs\weather\models\20210313\HRRR-SNOW24.png x1024 
y768'

I also tried using gxprint instead of printim, but the result was the 
same.  I am using grads 2.2.1

Any assistance would be appreciated.