I have already made a post about how to stop this (Click Here). This did stop the blurriness problem when uploading images to Blogger but lately, I’ve found for some unknown reason that the header image has been shrunk by Blogger when uploading, how frustrating. But there is like everything a solution.
Save your template before you change it.
The problem is caused by Blogger changing the format system for header images. It’s easiest to explain with an example. If you wanted your header image lets say 100x100px, and didn’t want to show title of description, Blogger will try to make the image the same size the title and description would have been:
expr:height=’data:height’ expr:id=’data:widget.instanceId + “_headerimg”‘ expr:src=’data:sourceUrl’ expr:width=’data:width’ style=’display: block’/>
Blogpress App Review
How to create favicon for your blogger website