as long as the tiles you insert into the exported bmp/dib have the exactly same colors as the others in that image (or i could say as long as its colors match the ones frim the palette) importing should work correctly.
a problem might be that you exported the image with a palette, then you moved / renamed / deleted the image or the palette file which has the same name as the image, except for its ending which is .pal not .dib . if the palette file and the image file or not in the same folder, dont have the same name or contain different colors there will be glitched green tiles.
if that is the mistake, all tiles of the tileset will appear green, not only the ones you inserted.
if thats the problem, let me know, if not, let me know too ;-)
a problem might be that you exported the image with a palette, then you moved / renamed / deleted the image or the palette file which has the same name as the image, except for its ending which is .pal not .dib . if the palette file and the image file or not in the same folder, dont have the same name or contain different colors there will be glitched green tiles.
if that is the mistake, all tiles of the tileset will appear green, not only the ones you inserted.
if thats the problem, let me know, if not, let me know too ;-)