Getting an error when run as a command line script

Hope someone can help with this. I'm trying to use this pdftotext class in a script that runs without a graphical interface - just to get some text out of a pdf. I'm running it just as a bat file. or command line and getting the error;

"Use of undefined constant IMG_JPEG - assumed 'IMG_JPEG' "
and it's stopping my script.

Any ideas how I fix this.

Thanks in advance

Yep, I'm getting the same error when trying the example scripts when running it on my local server and on my live server.
Any ideas would be helpful.

Es un error de php 8, en php 7.4 es ok