Function format:

|KE_FILEMANAGER_FILE_SIZE(_path_to_file_)|

where _path_to_file_ is the path (relative from images folder) and file name
it will return size in readable format: number and info (B, KB, MB, GB, TB, PB, EB)

Example:

|KE_FILEMANAGER_FILE_SIZE(media_content/mp3/|FILENAME|)|