The Image Widget is a really useful tool for putting an image, with a link, in the sidebar. You could also leave an image without a link if you wanted an image of yourself, a symbol or logo.
Small of course. Try widths of 200p, 250p, 300p. The heights will take of themselves with the native WordPress image sizer.
Watch the Video
Read the Instructions
Find the widget
Drag it over to your Primary Sidebar
The widget opens up and you see the instructions inside. Place your information in the fields provided