How can I make a link to invoke the download dialog box rather than it being shown.

Question

How can I modify

<a href="someimage">Download this</a>

in order to invoke the download dialog box?

Answer 1

Instruct the server to send it with a generic binary MIME type - binary/octet-stream is good for this. Standards conforming browsers will then just download it.

Answer 2

You could send a

Content-disposition: attachment; filename=someimage.jpg

HTTP header.