[Gimp-gui] Default export format usability

[Marty <marty heavyreckoning com>]

Hello,
This is feedback on the default export format always being PNG with a
requirement to always change it when exporting an image for the first
time.  PNGs are huge and do have their place but in the work I do I
nearly always export the final result to jpg for web use.  PNG is a very
bandwidth-unfriendly format for one-off stuff of modest importance.
IIRC, PNG is non-lossy; non-lossy is great unless it isn't a factor for
a particular workflow.

In the hope that devs are here I'd like to suggest either making the
default export format a setting in preferences or at minimum make the
most recent format selection in the current dialog sticky within a session.

I imagine others might be interested in this also.

TIA,
Marty G