Hello, Thank you for your question.
First of all you should use big images if you want to stretch them to full width. Please use at least 1920px. But at the same time don’t use too large images – they will be loading for a very long time.
The second step is to change settings of the blog post featured image:
0) Login to your website.
1) Go to any blog post.
2) Press the “Edit Site” button on the top left corner.
3) Open the left sidebar by clicking the 3 lines on the top left corner.
4) Find the “Featured Image” block and select it.
5) Open the right sidebar by clicking the “Settings” button (square icon) on the top right corner.
6) Select the “Block” tab.
7) Select the “Styles” tab (circle icon).
8) Find the “SCALE” section and select the “Cover” option.
9) Save the changes.
If you need more help, please contact us via email [email protected].
Thank you.