How to get FileInfo objects from the Orchard Media folder?

I'm trying to create a custom ImageFilter that requires me to temporarily write the image to disk, because I'm using a third party library that only takes FileInfo objects as parameters. I was hoping I could use IStorageProvider to easily write and get the file but I can't seem to find a way to either convert an IStorageFile to FileInfo or get the full path to the Media folder of the current tenant to retrieve the file myself.

public class CustomFilter: IImageFilterProvider {

    public void ApplyFilter(FilterContext context)
    {
        if (context.Media.CanSeek)
        {
            context.Media.Seek(0, SeekOrigin.Begin);
        }

        // Save temporary image 
        var fileName = context.FilePath.Split(new char[] { '\\' }, StringSplitOptions.RemoveEmptyEntries).LastOrDefault();

        if (!string.IsNullOrEmpty(fileName))
        {
            var tempFilePath = string.Format("tmp/tmp_{0}", fileName);
            _storageProvider.TrySaveStream(tempFilePath, context.Media);

            IStorageFile temp = _storageProvider.GetFile(tempFilePath);
            FileInfo tempFile = ???

            // Do all kinds of things with the temporary file

            // Convert back to Stream and pass along
            context.Media = tempFile.OpenRead();
        }
    }    
}

FileSystemStorageProvider does a ton of heavy lifting to construct paths to the Media folder so it's a shame that they aren't publicly accessible. I would prefer not to have to copy all of that initialization code. Is there an easy way to directly access files in the Media folder?

I'm not using multitenancy, so forgive me if this is inaccurate, but this is the method I use for retrieving the full storage path and then selecting FileInfo objects from that:

_storagePath = HostingEnvironment.IsHosted
    ? HostingEnvironment.MapPath("~/Media/") ?? ""
    : Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Media");

files = Directory.GetFiles(_storagePath, "*", SearchOption.AllDirectories).AsEnumerable().Select(f => new FileInfo(f));

You can, of course, filter down the list of files using either Path.Combine with subfolder names, or a Where clause on that GetFiles call.

This is pretty much exactly what FileSystemStorageProvider uses, but I haven't had need of the other calls it makes outside of figuring out what _storagePath should be.

In short, yes, you will likely have to re-implement whatever private functions of FileSystemStorageProvider you need for the task. But you may not need all of them.