Nice little image resizer that's using nuget package ImageProcessor

imageResizer.cs

using System;
using System.IO;
using System.Linq;
using System.Drawing;
using ImageProcessor;
using ImageProcessor.Imaging.Formats;

namespace CardResizer
{
    internal class Program
    {
        private const string DirectoryPath = "cardpack";
        private const string OutputDirectoryPath = "output";
        
        public static void Main(string[] args)
        {
            var resizeSize = new Size(456, 638);
            var outputFormat = new PngFormat();
            
            var files = Directory.GetFiles(DirectoryPath);
            foreach(var file in files.ToList())
            {
                var filename = GetFilename(file, DirectoryPath);
                var outputFilename = GetFullFilename(filename, OutputDirectoryPath);
                
                // cleanup
                DeleteIfExists(outputFilename);
                
                var data = File.ReadAllBytes(file);
                if(data.Length <= 0)
                {
                    throw new Exception($"There was a problem attempt to read byte data from image: {filename}");
                }

                using(var inputStream = new MemoryStream(data))
                {
                    using(var image = new ImageFactory(true))
                    {
                        image.Load(inputStream)
                            .Resize(resizeSize)
                            .Format(outputFormat)
                            .Save(outputFilename);
                    }
                }
                
            }
        }

        private static string GetFilename(string filename, string directory)
        {
            return filename.Replace(directory + "\\", "").ToLower();
        }

        private static string GetFullFilename(string filename, string directory)
        {
            return $"{directory}/{filename}";
        }

        private static void DeleteIfExists(string filepath)
        {
            if(File.Exists(filepath))
            {
                File.Delete(filepath);    
            } 
        }
    }
}