Per-format options in save dialog

Is your feature request related to a problem? Please describe.

Say I have this png I want to compress to a given rough size with jpg.
It's overly burdensome to pass through the general settings (especially if I'm experimenting with different values for quality)

Describe the solution you'd like

Irfanview has checkbox to enable a side panel depending on whatever the save format is, while GIMP will pop-up a new final dialog with extra settings when you click on the export button.

Describe alternatives you've considered

Not that I see this program should get really many other extra options, but I don't think the current options menu can scale much.
(also, arguably, it's not rare to want to save different files with different settings, despite anyway the default)

Additional context

Just as the first extra settings that pass through my mind, I guess png could see some setting for alpha, and jpg for chrome subsampling?

No files, tests, or entry points are identified in the issue, so begin by locating the save dialog and the existing general settings implementation. Done should provide format-specific options during saving, such as PNG alpha settings or JPEG chroma subsampling, without requiring changes to general settings.