What is the proper way to add button image?

Hello,

I am having a problem getting an image to be listed. For example I use the following shortcode in a page:

[dr_listings_btn view="always"]<img src="someimage.jpg" />Listings[/dr_listings_btn]

Although I can click on it and it works, It only shows the code, and not the picture? What's the proper way to get this image to be shown? The full URL doesn't seem to work nor does the just the image name itself...