Ah, that's normally because of RLE compression, which I know GIMP uses automatically when saving TGA files.
To prevent this, be sure to un-tick the 'RLE Compression' option when saving your textures.
That should make the texture show up without a red ring around it in TX Converter, meaning it can be converted properly.
To prevent this, be sure to un-tick the 'RLE Compression' option when saving your textures.
That should make the texture show up without a red ring around it in TX Converter, meaning it can be converted properly.