At quality 80-85 the difference is invisible at normal viewing distance and the file typically drops by 60-80%. The catch is that it is one-way: re-saving the JPG repeatedly compounds the artefacts each time. Keep the BMP as the master and regenerate the JPG from it whenever you need a new size. BMP根本不需要解码库,所以它仍然是嵌入系统和遗留Windows工具的安全交换格式。 JPG 丢失: 图像转换为 DCT, 量化和加密, 质量控制了丢弃多少 。
