inserting photo into text widget

Hello,
I am trying to insert a photo into a text widget. I am using a responsive child theme. I have searched the forum and have used several recommended code strings, and have had no success. The way I have been proceeding is to copy the recommended code into the widget, then go to my wordpress media library, copy the image link location and paste it into the code where it says “sampleURL” or something similar. I know this can’t be hard, I am just missing a step! Beware: Code and I do not get along. Please be very simple!
Thanks, Jim