ImgMetadataRemover/Image/OriginalFilenameOutputFormatter.cs

using System.IO;

namespace Image
{
    public class OriginalFilenameOutputFormatter : IOutputFormatter
    {
        private readonly string _rootDirectory;

        public OriginalFilenameOutputFormatter(string rootDirectory)
        {
            if (!Directory.Exists(rootDirectory)) Directory.CreateDirectory(rootDirectory);
            _rootDirectory = rootDirectory;
        }

        public string FormatOutputPath(string filePath)
        {
            var fileName = Path.GetFileName(filePath);
            var path = Path.Join(_rootDirectory, $"{fileName}.jpg");
            return path;
        }

        public static OriginalFilenameOutputFormatter Create(string rootDirectory)
        {
            return new OriginalFilenameOutputFormatter(rootDirectory);
        }
    }
}