Changing an audio block into an image?

Hey there, i am wondering if some one could assist me please. i am wanting to try and change my audio block into a jpeg image which ideally plays when pushed. i have found a way by using the css option to insert the picture into the audio block, but now i am unsure as how to readjust the size so i can see the whole entire picture.

i have included a screenshot of what i an see...

kind regards.

use this attribute under background-image

background-size: cover;

or

background-size: contain;