You should know its best practice to add at least one image to each blog post.
This doesn’t mean it needs to be displayed on your posts, as it can be added as a featured image so it only displays on your blog page or other archive page.
Wherever you decide to display your image(s), keep in mind you can customize them on a per posts/page basis if needed after you’ve already inserted them into a page or post.
Lets take a look at how you can make changes to any images you add in WordPress using the advanced image settings.
Image Properties
Here you can:
Change the width of your image border or remove it entirely by entering zero into the Border field.
Remove Default Image Border
If your images include a border by default or don’t include a border, you can use the advanced image properties to include, change or remove the border around an image.
Add Image Border
To add a border to uploaded images, simply enter the width of the border in pixels after you have inserted it into a post or page.
Child Themes Style.css File
If you open up your child theme’s style.css file, you’ll find a section for images.
You can easily find this section by opening the file using Notepad++ and entering image in the search function.
Go to Search > Find > Find Next and enter in the word Image.
Here you’ll find the default image border properties which relate to every image you upload and insert into a post or page.
This example shows the default image border properties for the Magazine child theme.
The avatar, featured images for pages & posts and all post images include a border of 4px thickness and grey color #eee.
You can edit these properties which will change the border properties on all inserted images on a site wide basis or use the image properties on a per image basis as shown above.