Handle max_kb in nokia.image-processing localmsg api

I tested with several images, the size of generated image is about 10%-20% larger than the given size which I think it's acceptable.
I checked the 45 screenshots in png with the same resolution 1366*768 on my laptop, the image sizes arrange from 50K to 540K, I converted these png images into jpeg with quality 100, then the file sizes arrange from 170K to 1.4M, so i'm afraid we can't just estimate the file size by the roughly-9-bits-per-pixel assumption.