Welcome to PokéCommunity! Register now and join one of the best fan communities on the 'net to talk Pokémon and more! We are not affiliated with The Pokémon Company or Nintendo.
The Ho Oh on the Wallpaper and on the Box art is the same Ho-Oh that was on the Pokemon Gold box except I used the pallette from the Fire Red sprite of Ho Oh to update it. Besides this is how Dusk Gold and Dawn Silver might look like for the DS. ( If you replace the GBA sidebar with a DS one and a few stylistic changes on the back)
On the whole, the pic's, the starter sprites, etc. are really impressive, but to make it MUCH more better, and a bit more beleivable, you could improve the set out on the back of the box, and fix up the very noticeable distortion around the ho-oh sprite on the front cover. The poster one is excellent tho ;)
I found the starters' art from Emerald and photoshopped it . I'll try to fix Ho-Oh ,and the weird coloring is from the leaf green art. But when I or some provides me with a higher res gameboy advance box art , then get prepared for a better version of the boxes.