Volkner GBA Overworld Sprites

GBA Formatted Volkner Overworld Sprite from the Pokemon Platinum Game!!

I took the DS overworld sprites and turned them into GBA formatted sprites. 
Each sprite must be 16x32 in order to be used in a GBA ROM, but also idc about credits, use them, who am i to stop you?

I don't own any percent of the Pokemon franchise, and I still can't understand why people think they have a right to say that their sprites can't be used by the public. Can someone explain this one to me? I'm not tryna be a dick, I genuinely just do not understand. I understand someone not wanting to have their work exploited, but at the same time, when you make something that is already a part of an established intellectual property, I feel like there isn't much room in terms of ownership from the person who made a picture of a character from an already-established I.P.

Can someone explain? Much luv.