Widget Style - Icon Type

I would like to use custom image instead icon from Icon Picker in Widget. Problem is, that icon has size about 70x70px, but if I choose image, and I upload it there, it is much more bigger, even tough I use smaller image.

Icon

large image

small image

Could someone help me how to set size of the image? I want to have image of virus in front of caption TEST (like alternative with icon).

Edit: This is widget (FT: Service) which I have mentioned about:

Topic icon images widgets Wordpress

Category Web

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