Hotline Miami 2: Wrong Number

Hotline Miami 2: Wrong Number

Hotline Miami 2
Hotline Miami 2 supports Steam Workshop to create and share custom levels and campaigns including original cutscenes with custom text, scripted behaviors by NPCs, and new characters.
How to change thumbnail for Hotline Miami 2 workshop item?
Can you please help me how to change it? I tryed to look it online but it didnt made me smarter...