So, you have an img element that doesn't have a src attribute, but it does have a background-image style applied.
I'd say that the gray border is the 'placeholder' for where the image would be, if you'd specified a src attribute.
If you don't want a 'foreground' image, then don't use an img tag - you've already stated that changing to a div solves the problem, why not go with that solution?
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