Is it possible to compress png format images into jpeg or jpg formats?

[OroChippw]

Is it possible to compress png format images into jpeg or jpg formats? I have a png wallpaper with a resolution of 8000*4113. I try to compress it. The console output is as follows

GPUJPEG rev 44ebd07
CUDA driver version:   12.5
CUDA runtime version:  11.6
Using Device #0:       NVIDIA GeForce RTX 3060 (c.c. 8.6)
[Warning] Encoder input file [E:\OroChiLab\GPUJPEG\data\input\1.jpg] should be raw image (*.rgb, *.yuv, *.r, *.pnm)!