[anonymfus]

>But what we need is a standard cross-browser way to request this behavior (prompt for download vs show), that by default standards-compliant browsers will comply with (I'll allow for users over-riding this default behavior with configuration, if the browser wants to support that, sure).

It would be annoying too. If I want to open bunch of such links as background tabs then I would need to temporally change this setting and don't forget to return it.

From usability standpoint (ignoring security and performance considerations) it's better to show me content and save button simultaneously. Then why do it only when site author wants it? Saving images is common operation and it would be better to show save button for every non-dynamic content.

Why modern browsers don't have save button (https://upload.wikimedia.org/wikipedia/en/0/0f/Opera_3.62.pn... ) on toolbar by default and want users to use menus for such common operation? Because designers don't have a place to put it without reducing usability for most common scenarios of browser use. Also save button was not replacement for "Save as" in context menu.

Do we have solution for situation when application is complex enough that there is bunch of operations which are used rarely but must be easily accessible in one click and could be context-dependant?

Yes. Microsoft's Ribbon.