why is it that LR does not show correct filesizes in the infodisplay, when i press <i> ?
dngs are 77mb, LR shows 55
tifs from those are 200something, LR says 88.
...
I think I have seen what you are describing in LR v5.7.
For instance starting with a NEF reported as 41.2 MB in Windows Explorer and comparing to LR info after pressing 'i' twice the LR result shows 36.2 MB (as shown below).
Exporting this file as TIFF produces a file size 206 MB reported by Windows.
Importing the file back into LR reports the 36.2 MB as shown for the original NEF.
Exporting as DNG gives a file size report of 146 MB (Windows) but 36.2 MB again after import to LR
Don't really know why I included the LR screenshot as regardless of file type the original LR file size 36.2 MB is always reported and Windows always disagrees as in this case reporting 41.2 MB
TBH it does not really bother me (Windows accurate - I believe) but it does appear to be curious behaviour
EDIT: LR Metadata panel does show correct size as already stated