Welcome to WebmasterWorld Guest from 220.127.116.11
Forum Moderators: not2easy
The way to override this is to zip your image; for example test.zip. Then you you create a link to test.gif and you will be presented with the download window.
PS. You can always right click and choose save as on any link and in effect download the file, but that is not what you asked for.
See [w3.org...] for technical details about Content-Disposition.
Now the hard part is getting the webserver to include this header. The easiest way to do it is via a script such as PHP, Perl or ASP. If you search for Content-Disposition and one of these scripting language you should come across some examples of how to do it.
Although, we've found it's best to just use a file format that will automatically go to download such as .zip, .pdf, or .doc files. If you force a document to download that would normally just appear in the browser, such as a JPG, people tend not to know how to open it later. And, if they are smart enough to know where to find it after they've downloaded it, and smart enough to know how to select the right program to open it, then they are smart enough to know to right-click on it and save it. IMHO.