Clean app markers increases the image file size

[hor0124]

XnView: MP 1.11.5 - 64 bit
OS: Windows 11 25H2

I use GIMP to fix Some old images.
When I try to use the "clean all other markers" option (from the clean metadata function) the image file size increases
The image has no other metadata information.

I noted the same behaviour from files before I even edited them (right after I scanned the image.)

How can this be? shouldn't clean shrink the file (or at least keep it the same?)

[cday]

Are you able to post example 'Before' and 'After' files for someone to inspect?

[user0]

check your format write settings in Settings>Formats>Write