We have found 2 software records in our database eligible for .cpt to .jpx file format conversion.
cpt to jpx conversion is a matter of export between two different raster formats from Corel PHOTO-PAINT bitmap images (.cpt) to JPEG 2000 format. If you do not have access to Corel software, it will be very difficult to achieve this export as Corel formats are usually not supported in 3rd party/free graphics editors/converters. But you can always try to use trial version of the software to just resave your files.
Updated: January 31, 2023
CPT
Files with cpt extension can be mostly encountered as raster graphics files from Corel PHOTO-PAINT app, part of CorelDRAW suite.
JPX
Files with jpx file extension can be found a special variant of the JPEG 2000 bitmap image format. Rather uncommon, proprietary version of JPG, with additional features, functions and generally higher quality. Also supports transparency.