Hello,

I have few CDs that I ripped into FLAC files, at that time I don't know how to embed the CUE sheet into the file, so that I can't use the image.

Now is it possible the rebuild the image?

Yes, one of the methods would be to use fb2k and encode into single file (Convert-> Run conversion, single file output).

Is it lossless compare to the original CD? Let's say the EAC ripping process is lossless, and of course the coding process to FLAC is lossless and the decoding process to single wav file is lossless?

Lossless means that coding and decoding of information is done without losing data. You end up with perfect files when extracting zip-archives, right?

EDIT: To clarify, you will in the end have the same information that you got from the extraction.

I am perfectly understand the meaning of 'lossless' although my English is bad

But, I think you're misunderstanding me. I'm wonder this --> "Yes, one of the methods would be to use fb2k and encode into single file (Convert-> Run conversion, single file output)." can make the identical wav image.

It would if you did not throw out the gaps.