Clever regex and LINQ in C#

Question

I have a directory. In this directory there are lots of various files. I need only thumbnails. So I wrote a regex to match those files.

Then, having all those matches files - I would like to make a dictionary that would have:

• the key as the extracted number from the filename (the matched number - see code below)

• the value as Image

      public readonly IReadOnlyDictionary<int, Image> thumbnails;
  
      ItemData(string directory)
      {
          this.directory = directory;
  
          var files = Directory.GetFiles(directory);
  
          Regex r = new Regex(directory + "\\thumbnail-([0-9]+).jpg", RegexOptions.RightToLeft);
  
          List<int> sizes = new List<int>();
          List<Image> images = new List<Image>();
  
          for (int i = 0; i < files.Count(); i++)
          {
              string result = r.Match(files[i]).Groups[1].Value;
              if (result != "")
              {
                  sizes.Add(Int32.Parse(result));
                  images.Add(Image.FromFile(files[i]));
              }
          }
  
          thumbnails = sizes.Zip(images, (s, i) => new {s, i}).ToDictionary(item => item.s, item => item.i);
      }
  

I truly believe this could be written in a very short and clear way. Could you please help me?

Edited solution

public readonly Dictionary<int, Image> thumbnails;

public ItemData(string directory)
{
    Regex r = new Regex("^thumbnail-([0-9]+)$", RegexOptions.RightToLeft);

    thumbnails =
        Directory.GetFiles(directory)
        .Select(f => new
        {
            file = f,
            match = r.Match(Path.GetFileNameWithoutExtension(f))
        })
        .Where(x => x.match.Success)
        .Select(x => new
        {
            size = Int32.Parse(x.match.Groups[1].Value),
            image = Image.FromFile(Path.Combine(directory, x.file))
        })
        .ToDictionary(x => x.size, x => x.image);
}

Answer 1

Here's the best I could come up with:

public void ItemData(string directory)
{
    var r = new Regex(directory + "\\thumbnail-([0-9]+).jpg", RegexOptions.RightToLeft);

    thumbnails =
        Directory
            .GetFiles(this.directory)
            .Select(f => new
            {
                file = f,
                result = r.Match(f).Groups[1].Value
            })
            .Where(x => x.result != "")
            .Select(x => new
            { 
                size = Int32.Parse(x.result),
                image = Image.FromFile(x.file)
            })
            .ToDictionary(x => x.size, x => x.image);
}

I had to change the IReadOnlyDictionary<int, Image> to IDictionary<int, Image> to make the assignment work.