Very much so. BMPは基本的に小さなヘッダを持つ未圧縮のRGB列であり、完全に損失なしで、巨大である。. That determines both the headroom available and whether the saving costs you anything in fidelity.
透明度の決定は，透明度の変更を行う段階である。 That is the step most people actually came for, and doing it after BMP を圧縮 rather than before it means the conversion works from the file you finally settled on.
