First off get your image. This image is pretty clean. It's ready to be imported.

Open your character and
hit the PCX Icon to add another sprite.
When you add the sprite, name it, and don't worry about what palette to use. Just use the image's palette
You should get the standard new palette warning.
Working in Piccolo Z2 when I made this. His last image, the image I was on when importing the new sprite, uses palette 20191. You can see the new palette isn't "IN" piccolo yet.
SAVE AND REOPEN YOUR CHARACTER.
Find your new image. It has the palette 0,310. Her wrist band is transparent, and the pink background is solid. We need this reversed!
Open Advanced Palette Editor (CTRL+P)
You can see the black, 0,0,12,0, is the first color and it's transparent, and the pink is in the middle of the colors and is solid.
Double click the First color, and set it's alpha to 255. So it becomes 0,0,12,255.
Click and drag the pink to the very first spot. You'll see the image looks like crap. This is GOOD.
Hit Commit changes to the current palette.
Hit Project > Save. Then you'll
hit the PCX Icon to add another sprite.
Import your image and name it something new. This time Under Palette:
Use FORCE the specified palette and put in your number
HEY! It's starting to look good! Except we want the bg image clear. So right in the screen you see you can
Double click the Pink Box
and set it's alpha to 0
Boom! FINISHED.
Save your Character
You can export your image using Sprites > Save Image and it should come out being paletted. Anyone who imports this sprite into FF3 should see a palette tha's exactly like my 0,310.