XnView Software

Note
when localizing strings with variables you have to:
- know what these variables mean to avoid issues AND
- follow exact variables/words order, especially when working with lists, where other options exist

Example
'Duplicate files naming' setting has 5 options (Settings>General>File operations):
   <Filename> - Copy (#) default
   <Filename>-Copy (#)
   <Filename>-(#)
   <Filename>-#
   Copy (#) of <Filename>

• Copy (#) of <Filename>
  uses 2 strings when creating 1st and nth copies:
     Copy of %1%2
     Copy (%3) of %1%2
     where
        %1 - name
        %2 - .ext
        %3 - iterator

Issue
lets
1. select 'Copy (#) of <Filename>' and switch languages in v1.9.8
2. copy TEST.jpg few times to check how app will name files

• English
  • correct
    Copy of %1%2
    Copy (%3) of %1%2
    Copy of TEST.jpg
    Copy (2) of TEST.jpg

• Armenian
  • incorrect - unrecognizable ext
    Պատճենվում է %1%2-ից
    Պատճենվում է (%3)-ը %1%2-ից
    Պատճենվում է TEST.jpg-ից
    Պատճենվում է (2)-ը TEST.jpg-ից
  • correct
    Պատճենվում է %1%2
    Պատճենվում է (%3)-ը %1%2

• Chinese (both)
  • incorrect - repeats already existing option
    %1的副本%2
    %1的副本（%3）%2
    TEST的副本.jpg
    TEST的副本（2）.jpg
  • correct
    的副本 %1%2
    的副本 (%3) %1%2

• Finnish
  • incorrect - 0 length file
    Kopioi (%3) %1%2:sta
  • correct
    Kopioi (%3) %1%2

• Hungarian
  • incorrect - repeats already existing option
    %1 másolata%2
    %1 másolata (%3)%2
    TEST másolata.jpg
    TEST másolata (2).jpg
  • correct
    Másolat %1%2
    Másolat (%3) %1%2

• Japanese
  • incorrect - repeats already existing option
    %1のコピー%2
    %1コピー(%3) %2
    TESTのコピー.jpg
    TESTコピー(2) .jpg
  • correct
    コピー %1%2
    コピー(%3) %1%2

• Korean
  • incorrect - unrecognizable ext
    %1%2의 사본
    %1%2의 사본 (%3)
    TEST.jpg의 사본
    TEST.jpg의 사본 (2)
  • correct
    의 사본 %1%2
    의 사본 (%3) %1%2

• Turkish
  • incorrect - unrecognizable ext
    %1%2 in Kopyası
    %1%2 in (%3) Kopyası
    TEST.jpg in Kopyası
    TEST.jpg in (2) Kopyası
  • correct
    Kopyası in %1%2
    Kopyası (%3) in %1%2

• Ukrainian
  • incorrect - does not change filename of n copy due to mistype
    Копіюється (%2) з %1%2
    Копіюється (.jpg) з TEST.jpg
  • correct
    Копіюється (%3) з %1%2

Conclusion
To avoid most of the issues listed above - ORDER of variables and words 'Copy' and 'of' (if applicable) MUST remain the same.
No need to be creative with your 'localization', use direct translation, especially in cases where other options are already available in the combobox/list/etc.