We have a TEST and a PROD environment set up. I was able to add a excel spreadsheet to our TEST environment but when I tried on PROD I received an PHP error. Any suggestions?
Attachment shows steps I took and the error message.

"Cannot find any of the supported PHP image extensions!"

Depending on your OS/PHP combo you need to install the GD or imagick library.
How that is done depends on your Linux oder Windows PHP combo.

KCfinder is looking for a an extension to create thumbnails of graphic images.
If no graphic library can be found the error is shown.