Pop up to save image in asp.net

Question

Hi All,

I am using asp.net 3.5 and C#.

I have a image which I want user can download. Like, there would be a download button or link. When user click on this link he will be prompted with a pop up to save that image to his desktop.

I have tried with

<a href ="path" > </a>

but it is opening the image in other page, I want user to be prompted to either save or view the image,

please help

Thanks in advance

Answer 1

You need to write an IHttpHandler that serves the image along with a Content-Disposition header.

For example:

Response.AppendHeader("Content-Disposition", "attachment; filename=\"MyImage.png\"");
Response.TransmitFile(path);

You would probably pass the image name on the query-string.
If so, make sure it doesn't contain / or \, or attackers will be able to read arbitrary files.

Answer 2

You need to have another page or, better yet, an HttpHandler, that takes the image path as part of the query string or as a post parameter that will send the response with Content-Disposition set to attachment. Setting the content disposition this way will cause the browser to display the file download dialog. A slightly easier way, though it depends on the user doing something extra is simply to have the link open the image in a new page and let the user right-click on it and do a "Save As".

<a href="/path/to/handler?image=name-of-image-file">Download</a>

or

<a href="/path/to/image" target="_blank">
    Load Image in New Window then Use Save As</a>