UX: Remove background image after image has loaded (PR #13642)

If an image has a smallUpload, that may be set as the background-image on the img element, and the img element set to use lazy loading. When the browser decides to load the src of the image element, it is rendered on top of the existing background image.

However, if the image proper has a transparent background, the background image may be partially visible through the transparent portions of the image.

This change creates an onload event that removes the background image when the image proper has completed loading.

GitHub

Can we use removeAttribute("style") on the element? Would have cleaner markup, instead of many empty style properties.