image in header problem

when i use img:[image_path] so i display an image in a grid’s header the image gets automatically width and height of 18 pixels so if my image is 16 pixels of width and height it becomes blurry.

How do i fix this problem ???

You can place any required html in your header.
For example:

i know that but WHY did u hardcoded the resolution of the image when developed the img:[] solution ???