Original image.
No compression, 13kb

Compressed at 20%, 13kb

Compressed at 40%, 8.8kb
I would use this one even though the roof is not as defined.

Compressed at 60%, 6.6kb
This one is useable, probably because of the photo size. Most people wouldn't notice the blur on the roof.

Compressed at 80%, 4kb

Compressed at 99%, less than 1kb

Original, saved at 256 colors, 4kb

Transparent background
done per tutorial, 50 colors 7kb

I used the gif wizard on this and
don't remember how many colors I used.
This is the one I would use, 6kb