在高级别，您需要获得。 jpg到一个NSBitmapImageRep对象，然后让框架为你处理转换。

At a high level, you need to get the .jpg into an NSBitmapImageRep object and then let the frameworks handle the conversion for you.

以下是MAC的链接：
如何使用Objective C将.jpg图像转换为.bmp格式？

Below is the link For MAC: How to convert .jpg image to .bmp format using Objective C?

有一个命令行工具可以帮助你从GITHUB

There is a commandline tool which might help you from GITHUB

https://github.com/tonybeltramelli/TMXResolutionTool/

也是***的事情是在UIImage中获取图像然后将其转换为bitMap。

Also the best thing would be to get the image in UIImage and then convert it to bitMap.

https://github.com/PaulSolt/UIImage-Conversion

这对你有帮助。

问候，

Anil