I don’t know what a Kib is either (and I am a computer programmer by trade). I am guessing it is a kilobyte (kb).
If it is not already a JPG, try converting it to a JPG. A BMP file takes more room for the same size image. One can also do things like increasing the compression and reducing the colors used.
If you don’t have software to convert images let me know and I can do it for you.