How can I fix HTML issues in my product description?

[powwow]

Hi !

First of all, please understand that my English is not good.
I designed on the description page by using photoshop and saved html with images (save for web) in a same folder.
Products > add product > description> '</>' tab, and then I copied and pasted all html. However, no image appears on the product description page.

 

The description page I designed on has a lot of content and looks awkward because of the background color.

Furthermore, the horizontal size of page is the same, and the vertical size is different. But, when I uploaded them by tap 'Insert image' not a html, all horizontal sizes are applied differently even if I set a same size at the bottom.

 

Please let me know how to upload the description through html.

Thank you in advance.