This program (Perler) may prove useful for producing pixel art from photos etc. -- it's free, and you get lots of options and control:
...but it is not intended for pixel art apparently! You'll need to take a screen shot and then play around with it.
What I started with -- Reduced -- (original image is 1820 x 2730 pixels)...
Imported into Perler and reduced in size and colour palette (note "Enlarged by 4x for your viewing pleasure" at top left)
Screen grab imported into Photoshop (any editor would do) and reduced by 4x... (Vertical green line is one pixel wide)
Exported gif file -- 1.52 k.
(Ooops! Ha ha! OR, alternatively, you could go to the Menu at the bottom ("Palette, Dithering..." etc.), and under "General", you will see "Export Image". The program will only export PNG format, but I guess that's ok. The sizing part seems a bit quirky, so you may still want the "Screen Grab" method as a backstop.)
I could have tarted it up somewhat -- this is raw production. Better than many other programs I've seen. Hope this may be useful for some people.