I have read this graphic novel between 2000 and 2005 in the library. It was an around Din A4 sized hardcover book, but thin. Maybe original France, but I read it in German language. The title could be something with uppercase letter "X".
The title or one of the first pictures showed a soldier in World War (WW2 I assume, but maybe WW1). I assume he was dead, hanging in barbed wire. There was the impression of angels wings in this picture. I do not remember, if the barbed wire fored this shape, or if it was a shadow-like second picture "behind" the first picture.
The story was something dark, with god and angels. So I hope I meet the Scifi.SE criteria. It was a bigger timeframe than only World War. The different times were woven with each other. It leaves the impression of a reasoning that there must be angels, so the described picture could be some kind of "proof" in the whole story. I could remember no "action", the whole feeling was "sadness".
I remember how impressed I was from the pictures. They were like pencil drawings. Not so clean like this ones which are made with a computer's help. I cannot remember some colors, so I assume it was almost in black and white, maybe some sepia or brown on the title.
I wish to see these pictures again, to explore my long-lasting impression of it.