modelsim保存波形图为图片报错：image file format "bmp" is unknown

在波形窗口依次点击 File-->Export-->Image
如果版本低于2020.2，会报错：

解决方案为：
在命令框输入：package require Img

解决方案来自Why can't I export the wave image in bmp format in the ModelSim-Intel® FPGA Edition and Questa-Intel® FPGA Edition simulator?