Disable direct access to images

Question

I am making a little family photo album, with the intention to maybe open it to other people to store images later.

I upload the images to ~\images\, then resize them 3 times (Normal view ... thumbnail and a tiny version) and move them to ~\images\thumbs, ~\images\normal, ~\images\tiny and then move the original to ~\images\original.

If a user knows a file name, they can just goto http://mysite.com/images/normal/filename.jpg for direct access.

I'd prefer that not to be available to them.

So, is there a way to change the ImageUrl of the asp:Image control, to rather read from a non-accessable folder? And would this be a performance hit? I'm thinking something like (Not sure if it's possible) reading the image into s Steam, and somehow setting the ImageUrl or what ever, to read from the stream?

Hope you can assist.

Answer 1

The answer is yes. You can use a special format of img src which will embed the image directly in the page.

Instead of the URL, you would use the following format:

<img src="data:image/png;base64,..." />

where data specifies the mime type of your image and the ... after base64, is the base64 encoded contents of the image.

This behavior is defined by this RFC.

Here is an example:

In the HTML:

<img id="MyPicture" runat="server" border="0" />

In the code-behind:

    protected void Page_Load(object sender, EventArgs e)
    {
        MyPicture.Src = @"data:image/gif;base64," + EncodeFile(Server.MapPath(@"/images/test.gif"));
    }

    private string EncodeFile(string fileName)
    {
        return Convert.ToBase64String(File.ReadAllBytes(fileName));
    }