I'm going to answer this using ImageProcessor since your own answer uses the library. Disclaimer. I'm also the author of the library.
You're really not best using an ActionResult for processing images as it will be horribly inefficient. It run's far too late in the pipeline and you will have no caching.
You're much better off installing the Imageprocessor.Web package and implementing your own version of the IImageService interface to serve your images from the database. (On that note storing images in a db unless you are using blob storage is never wise either)
Implementing the IImageService interface allows you to utilise the url api within the library with a specific prefix to identify which image service to use. For example, remote image requests are prefixed with remote.axd to tell IageProcessor.Web to excute the RemoteImageService implementation.
This has the benefit of caching your images so subsequent requests are returned from a cache rather than being reprocessed upon each request.
Here is the full implementation of the LocalFileImageService which is the default service for the library. This should be able to serve as a guide for how to implement your own service.
namespace ImageProcessor.Web.Services
{
using System;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;
using System.Web;
using ImageProcessor.Web.Helpers;
/// <summary>
/// The local file image service for retrieving images from the
/// file system.
/// </summary>
public class LocalFileImageService : IImageService
{
/// <summary>
/// The prefix for the given implementation.
/// </summary>
private string prefix = string.Empty;
/// <summary>
/// Gets or sets the prefix for the given implementation.
/// <remarks>
/// This value is used as a prefix for any image requests
/// that should use this service.
/// </remarks>
/// </summary>
public string Prefix
{
get
{
return this.prefix;
}
set
{
this.prefix = value;
}
}
/// <summary>
/// Gets a value indicating whether the image service
/// requests files from
/// the locally based file system.
/// </summary>
public bool IsFileLocalService
{
get
{
return true;
}
}
/// <summary>
/// Gets or sets any additional settings required by the service.
/// </summary>
public Dictionary<string, string> Settings { get; set; }
/// <summary>
/// Gets or sets the white list of <see cref="System.Uri"/>.
/// </summary>
public Uri[] WhiteList { get; set; }
/// <summary>
/// Gets a value indicating whether the current request
/// passes sanitizing rules.
/// </summary>
/// <param name="path">
/// The image path.
/// </param>
/// <returns>
/// <c>True</c> if the request is valid; otherwise, <c>False</c>.
/// </returns>
public bool IsValidRequest(string path)
{
return ImageHelpers.IsValidImageExtension(path);
}
/// <summary>
/// Gets the image using the given identifier.
/// </summary>
/// <param name="id">
/// The value identifying the image to fetch.
/// </param>
/// <returns>
/// The <see cref="System.Byte"/> array containing the image data.
/// </returns>
public async Task<byte[]> GetImage(object id)
{
string path = id.ToString();
byte[] buffer;
// Check to see if the file exists.
// ReSharper disable once AssignNullToNotNullAttribute
FileInfo fileInfo = new FileInfo(path);
if (!fileInfo.Exists)
{
throw new HttpException(404, "No image exists at " + path);
}
using (FileStream file = new FileStream(path,
FileMode.Open,
FileAccess.Read,
FileShare.Read,
4096,
true))
{
buffer = new byte[file.Length];
await file.ReadAsync(buffer, 0, (int)file.Length);
}
return buffer;
}
}
}