>Grump grump grump grump grump grump
The image is for you, Anon.>>9623
Make a sprite to the proportions of an RM2k3 sprite set. You can find templates for the spritesheets on the internet. Make a normal view sprite of your character facing downwards, work off that.
Image files in RM2k3 need to be at a colour depth of 256 colours. You can use software like photoshop, Irfanview (I use this, it's quick), and anything that let's you manually set colkour depth. I recommend avoiding using MSpaint to lower the colour depth because the messes with the colours too much.
Look up spriting tutorials or study the sprites used in other games.