The only lfp to jpeg conversion we know about is potential export of RAW digital images from Lytro Lightfield cameras (.lfp) as standard JPEG pictures, which can be done with the software provided by Lytro, called Lytro Desktop.
Perhaps the same can be done with any photo graphics editor with support of LFP format, but we do not know about any at the moments. So perhaps using Lytro is indeed the only way how to handle and export these files.
Updated: November 1, 2023