You can use the Combo Blocks plugin to set the custom “Thumbnail Size” for the “Image” Block. This article will help you to set the thumbnail size for the “Image” block.
To begin, insert the “Image” block.
![How to set custom thumbnail size for image? 1 HnF9bXA](https://i.imgur.com/HnF9bXA.png)
Now select an image source and select an image.
![How to set custom thumbnail size for image? 2 hFwjSot](https://i.imgur.com/hFwjSot.png)
Click on the “Image” tab.
![How to set custom thumbnail size for image? 3 66RboHl](https://i.imgur.com/66RboHl.png)
Click on the “Choose” button from “Thumbnail Size” and select a preferred size.
![How to set custom thumbnail size for image? 4 gqpBwBn](https://i.imgur.com/gqpBwBn.png)