[Oleksandr Kramer]

Just drag the image to the material/render preview or use the auto-assign preview tool. Note, that these options are available only for material libraries, not for scene materials.

https://3d-kstudio.com/tutorials/auto-assign-preview-for-3d-models-and-materials/

https://youtu.be/oWY_wSfyD2I?t=150