Follow these steps to customize the case study thumbnails on your portfolio:
Go to the Portfolio Editor.
Hover over an existing case study’s thumbnail.
In the thumbnails top-right corner click Options.
Choose Set Thumbnail.
Pick a thumbnail image from the Generated Thumbnails.
Click Change Thumbnail.
You can also upload your own thumbnail:
Go to the Portfolio Editor.
Hover over an existing case study’s thumbnail.
In the thumbnails top-right corner click Options.
Choose Set Thumbnail.
Click Upload your Own to upload your own image.
Select your file (max. 5 mb).
Click Change Thumbnail.
You can always find the ideal case study thumbnail size in Set Case Study Thumbnail modal, under Upload Your Own.