How do I add custom battlers?

When I try adding a custom battler graphic, it keeps the white box around it. How do I fix this?

press f10, click battlers click import locate file and click on white, then click ok.

press f10, click battlers click import locate file and click on white, then click ok.

It does not let me click on white like when I import a tileset.

Does the file have a .png extension?

Does the file have a .png extension?

No... should it?

I switched it to a PNG file and it worked, but when I went to add another PNG pic it did the same error of not letting me choose a colour.

Hmmm, i remember certain extensions being "damaged" by certain programs... the bitmap file with an alpha channel NOT being recognized because of weird compression, or color system, or something. Even rmxp will react weirdly with those wacky compressions. To be sure, format the bitmap like that:
 If you have photoshop, re-save it in "PNG" with an alpha layer, then when the file extension preferences shows up, select:
first box: none
second box: adaptable (last choice)
 If you don't have a good bitmap editor... then you're in trouble, and should get one quickly.