Optimal Image Sizes for WordPress
* WordPress Background Images: 1920 x 1080
* Header Banner Images: 1048 x 250
* Thumbnail Images: 150 x 150
* Landscape Featured Images: 1200 x 900
* Portrait Featured Images: 900 x 1200
* Blog Post Images: 1200 x 630
* Logo Images: 200 x 100

For themes that use rectangular featured images: 1200×687 pixels
For themes that use square featured images: 600×600 pixels
* Hero Images: 2880 x 1500
* Fullscreen slideshows: 2800 x 1500
* Gallery Images: 1500 pixels x auto width

wordpress site icon size / favicon:
32x32px
512 x 512 pixels
180x180px app icon for iOS up to the iPhone 6+.
192x192px Android/Chrome app icon.
270x270px medium-sized tile

What’s the ideal image size for achieving rapid, high-quality visuals that appear crisp and adaptable on desktops, tablets, and mobile devices? WordPress has a few recommended sizes, such as:
WordPress Background Images: 1920 x 1080
Header Banner Images: 1048 x 250
Thumbnail Images: 150 x 150
Landscape Featured Images: 1200 x 900
Portrait Featured Images: 900 x 1200
Blog Post Images: 1200 x 630
Logo Images: 200 x 100
Hero Images: 2880 x 1500
Fullscreen slideshows: 2800 x 1500
Gallery Images: 1500 pixels x auto width

Banner:
For themes that use rectangular featured images: 1200×687 pixels
For themes that use square featured images: 600×600 pixels