Why can't I retrieve the image URL from the asset folder?

[nealrm]

I'm trying to return the url of an image. I can see the image in the asset folder in the code editing area. This is the code I am using: {{ about-bckgrnd_2048.webp | asset_img_url }}

It keep returning the "no-image" gif url. I have tried multiple similar filters, none are finding the image. Any suggestions?