ASP.NET send image
last modified October 18, 2023
In this article we show how to send images from an ASP.NET application.
ASP.NET is a cross-platform, high-performance, open-source framework for building modern, cloud-enabled, web applications. It is developed by Microsoft.
HTTP Content-Disposition
The Content-Disposition response header is a header indicating if the content is expected to be displayed inline in the browser or as an attachment, that is downloaded and saved locally.
Media type
A media type or MIME type is a specific metadata information which indicates the nature and format of a file. Servers can send various types of files including text files, HTML files, PDF, Excel or image files.
ASP.NET send image inline
In the first example, we send an image inline.
The Results.File function writes the file at the specified path to
the response.
var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
app.MapGet("/image", () =>
{
var mimeType = "image/png";
var path = Path.Combine(builder.Environment.ContentRootPath,
"images/sid.png");
return Results.File(path, contentType: mimeType);
});
app.Run("http://localhost:3000");
We have one endpoint which sends an image. We do not specify the
Content-Disposition; the default is inline.
var mimeType = "image/png";
We define a mime type. It is a PNG image.
var path = Path.Combine(builder.Environment.ContentRootPath,
"images/sid.png");
We build the path to the image.
return Results.File(path, contentType: mimeType);
We return the image to the client with Results.File.
ASP.NET send image as attachment
In the next example, we send the image as an attachment.
var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
app.MapGet("/image", (HttpResponse response) =>
{
var mimeType = "image/png";
var path = Path.Combine(builder.Environment.ContentRootPath,
"images/sid.png");
response.Headers.Add("Content-Disposition", "attachment;filename=sid.png");
return Results.File(path, contentType: mimeType);
});
app.Run("http://localhost:3000");
We need to set the Content-Disposition to attachment.
app.MapGet("/image", (HttpResponse response) =>
To change a header, we need the HttpResponse object.
response.Headers.Add("Content-Disposition", "attachment;filename=sid.png");
We add the Content-Disposition header.
ASP.NET send image with view
The following example shows how to send an image within a static HTML file.
var builder = WebApplication.CreateBuilder(args);
builder.Services.AddControllersWithViews();
var app = builder.Build();
app.UseStaticFiles();
app.UseRouting();
app.UseEndpoints(endppoints =>
{
endppoints.MapDefaultControllerRoute();
});
app.Run("http://localhost:3000");
We have a MVC web application. We set up routing, controllers and views.
app.UseStaticFiles();
We enable static file serving. The static files are located in
wwwroot directory by default.
using Microsoft.AspNetCore.Mvc;
namespace ServeImageEx.Controllers;
public class HomeController : Controller
{
[HttpGet("image")]
public IActionResult Image()
{
return View();
}
}
We have one action in the HomeController. It simply returns a view.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Image</title>
</head>
<body>
<h2>Sid the sloth</h2>
<p>
<img src="~/images/sid.png">
</p>
</body>
</html>
In the view file, we have an img tag. It points to the PNG file
in wwwroot/images directory.
In this article we have served image files from an ASP.NET application.
