There is no data loss with the tif compression choices.
Actually the JPEG compression option introduces data loss on the initial save of a file and subsequent saves if changes are made.
#1
1.)
ok, if you want to be critical about things, yea, very little that most won't know about.
2.)
It depends on what kind of edits you did before the last save. Pixel edits, well, again, little loss that most won't see if you use the high quality setting, "low compression."
If you want me to come clean, well, you'll have some very small loss of pixel clarity.
geez.
#2
What MO meant to say is that yes - you will experience the same amount of jpeg degredation that you will experience as if you simply just saved as a jpeg....
#3