Checked on XP and Windows 7 x64:
The EXIF information tag is lost when selecting 'Skip if output size is greater than the original'.
Selecting this option blocks the exif_copy.exe from executing due to a FILE LOCKED WITH ONLY READERS error.
This is a bug and overrules the 'Keep EXIF information while compressing' option in this case.
Unchecking the 'Skip if output size is greater than the original' option restores the 'Keep EXIF information while compressing' option again.
To sort the files that are greater than the original, you have to inspect and delete them manually. It would be nice to have Caesium to add a warning mark in the filename or have an option to copy the original file in this case. Sorting on the column Ratio and deleting ratios with a positive number won't work because the list cannot be sorted yet.
Anonymous