Images in upcoming events widgets in elementor pro

Hello,
I am working with Elementor Pro and when i want to insert the upcomings events widget the banner-images are poor quality. I tried to find the corresponding template to change the display setting for these images but I don’t know which one it is.
Can you help me and tell me which template and which parameter I can change to improve these images? Thank you in advance for your help.
Best regards
Isaline K.