White frame around images in WoW Addon

I am having some trouble with my World of Warcraft addon. Whenever I display my TGA files in the addon, there is a thin white frame around them. The same happens when I convert them 开发者_开发问答to BLPs.

When I look at the images themselves with Preview, there's no white frame, but WoW decides to display one.

How do I resolve this?

---

I'm guessing you are using TGA files with an alpha channel and the "thin white frame" is about a pixel or less.

This is usually the effect of a matte that is placed under the opaque edges of the artwork prior to calculating the alpha channel. The solution is to generate your own alpha channel and feather the edges in by a pixel or so thus masking the matte.

The explanation is actually a tad more complex than this, but the method works.