Hello everybody how can i make my header image fits all resolutions without leaving a gap between left and right.
Example:If i view my blog in 1920x1080 there is a big gap between the left and the right but if i view it in 1280x1024 the header image perfectly fits in.

Make your header image as wide as the widest width you allow your screen to be. It will be cutoff at one or both edges (depending on what you choose) so put the important part of the image in the section that won't be cut off.