I have just found great trick to change ms-office default .bmp image format to .jpeg image format. please see this link: - http://limbomatic.com/change-ms-paint-default-image-saving-format-bmp-to-jpg
Here ( http://fixmypaint.com/ )you can find nano software that changes format "manually" for you. Also adds "Save As" functionality like in Photoshop.
while saving paint image you can change the format to jpg or something then we can use it as jpg easily..
This is what FixMyPaint does - it changes it for you during saving process. Automatically. Super quickly. You'll feel like jpg is already a default )