Hi,
First, please note that this thread is 8 years old.
We've actually improved the view file edition recently and there is now a simple drag & drop mechanism to move around the different elements of most view files:
www.hikashop.com/home/blog/471-hikashop-4-4-3.html#drag
Now, we don't have yet the capabitlity to add new areas configurable like a page builder. That's something we want to work on in the future. That would indeed allow you to add new areas like a logo with zero HTML knowledge.
For now, you need to add the img tag yourself in the HTML code as Xavier said.
PHP knowledge is not required for that. In fact, if you really don't want to edit the view file, you can add your img tag at the end of the "store address" setting of the HikaShop configuration. That way, the image will be placed just after the store address on the invoice.