Little Spirou

I've never understood, why is Spirou dressed as groom. Of course it's not affecting the comics (and cartoons made after them) in bad way. :)

Sometimes the simplest explanation is the best.  ;-)
In the very first version, before the war, Spirou was just a comic strip for a magazine,
and Spirou was a groom for the newspaper "le moustique"  (mosquito)   :-)
He was just a mischievous boy playing tricks.
The drawing and the little stories were very simple.

This was before Franquin and before the albums of Spirou.
Franquin is considered as being the real creator of Spirou.

And I guess Spirou retained his outfit, because it became essential part of his design, didn't it ?

Yes, you are totally right.  :-)
Franquin kept the groom uniform of course, which is an essential feature of Spirou,
though he considerably improved the whole design and the characters, 
he gave them personality, and also he created interesting stories with a plot.

Cute! I haven't seen much of the comic, in which he was a kid. I rather remember him as a teenager (and mostly from the cartoon sreies I once mentioned here), so his kid-form astonishes me :D
By the way, Happy New Year to you as well ;)

You did not miss anything at all, believe me!
Even if the design of the little Spirou is cute and fun, it is just a succession of silly little jokes, there is no story.
I prefer the "real" Spirou.  :-)

sooo adorable^6

Thank you so much! :D