[SurroundSound] SACD playback, “image” files howto

Dear friends,
pls forgive if it's been already replied, but couldnt find it in our group history or online.
I got some SACD iso images where the audio section is within the ISO file, but... I see some impossibly huge jpg files within the Artwork folder: and these files are clearly NOT image files (from 500MB to 2GB in dimension...).
Do you know what are they intended for? (hope not a virus...).
You can find them for instance in Dana Winner, Timeless 2016 compilation, etc.
Many thanks, ciao
Luke

--
--
You received this message because you are subscribed to the Google Groups "SurroundSound" group.
To post to this group, send email to SurroundSound@googlegroups.com
To unsubscribe from this group, send email to SurroundSound-unsubscribe@googlegroups.com
For more options, visit this group at http://groups.google.com/group/SurroundSound

---
You received this message because you are subscribed to the Google Groups "SurroundSound" group.
To unsubscribe from this group and stop receiving emails from it, send an email to surroundsound+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.