Lossless JPEG2000 to PDF Compression

If I use lossless JPEG 2000 files, will the compression automatically be lossless?

 

By @Jalen30051005ql1u

No. Compression is driven by the export settings.

Also, when I decided to export the images, I had to use 72 dpi instead of 96 dpi, and 96 was the dpi of my input images. How do I fix that?

By @Jalen30051005ql1u

You had to use? You could have set the 96ppi value.

If the file has been downsampled, you need to export again. If the file has not been downsampled, there has been no change to the pixel density.