OPTIMIZATION: Optional Dithering for Better Image Quality and Faster Processing

[SemAiSoft]

The existing implementation is great - particularly I like the support for various image formats, yet I see a room for optimization.

There are many uses cases, where the supplied image is already in pure monochrome of black & white. This is especially true, if the image is being generated solely for the thermal printers - for example, converting a bootstrap table to image.
Reprocessing this same image by flattening and dithering causes the images to lose some quality (unnecessarily) in addition to the processing overhead and time cost.

The .image converting images to black and white can become optional (in which case, the developer/user bears the responsibility of right image), by taking falsy value of the fourth parameter (dithering) to mean 'OFF'.
I hope this can be looked into, THANKS for the GREAT WORK!