For this step we will be using IRFranView and Gimp
First off, open up IRFranView and the table of overworlds which you have chosen, for this tutorial I will use a set from Zelix's sheet.
Link to Zelix's sheet here
Now to index the whole set at just one time go to
Image.>.Decrease color depth...
Once in that dialogue make sure you UNCHECK Floyd-Steinberg Dithering unlike the image. Now click 16 colors and press ok. Now save it as a bitmap to wherever.
So where does gimp come in on the indexing? Well it is a small step, but VERY important for your Overworld to come out with the smexiness you want :3.
Now in Gimp, go to here
From here click on the arrow on the top right and press edit colormap, now put your transparent color as the first color! Now your done indexing your table of OW's.
Step 2: Frame by frame easy insertion!
For this step we will be using Gimp and OWE Rebirth/Darthatron's
Now in gimp with your table we must make them into frame by frame representations such as all ow's in the game.
A frame of an OW of a normal person is 16(width)x32(height) pixels.
But we cannot just start any old one in Gimp, no we must reopen your table and have two of it open, to do this just save your table as another name.
Now with that we will resize one of them to 16x32 pixels.
Now you must paste the first frame of your sprite into here. Now save it as 1.bmp. Do this for every frame and keep saving up one more number.
Once you are done you have all your frames ready to insert.
Now in OWE Rebirth/Darthatrons go to the OW you want to edit, press import Sprite...
Now browse and choose your image, also check import pallet. Then press OK! Frame one = done!
Now do the same thing for each frame and you are done!
My problem is the palette I'm importing with my new OW. That palette is also used for some other OWs, and they look extremely weird now :p
I had the same problem, so found a simple solution. I was importing sprites into FR from Emerald, and they badly screwed up my palettes, so I reverted the palettes (I had a backup of the rocket's normal sprite with the old palette) and switched the old sprite's palette to one that isn't used for anything, 19 in this case. Then I imported the new sprite again and imported the palette, swapping out the old unused one with the new one. The new sprite is the only one in the whole game to use palette 19 anyway, so nothing else was screwed up.
EDIT: I found that the hero sprites use the odd palettes, so it may be a good idea to make your hero sprites look normal with the palettes used by regular NPCs.
It seems that I can't put two good customized Overworld sprites in the same map. I tried putting Espeon and Arcanine OW sprites together, both having different palettes of course.. and well the sprite that was first applied gets screwed up by the following sprite. In my case, if Arcanine(turns purplish) was first its color gets screwed up in gameplay by Espeon. Same when Espeon(turns orange) is first the color it then gets screwed up by Arcanine.