TextureEditor: Don't crash on exporting texture packs with indexed te…

…xtures

TextureEditor/MainForm.cs

@@ -1012,6 +1012,7 @@ private void exportTexturePackToolStripMenuItem_Click(object sender, EventArgs e
 								bmp = ProcessIndexedBitmap(tex, indexedfmt);
 								bmp.Save(Path.Combine(dir, tex.Name + ".png"));
 								bmp.Save(tex.TextureData, ImageFormat.Png);
+								exportData = tex.TextureData;
 							}
 							// Non-indexed
 							else