The original image is visible underneath the placeholder while loading

[TonyBogdanov]

Description

When preload is set, but there is no placeholder specified, or it resolves to a transparent / translucent image, the original image underneath is seen being loaded. If the image is progressive, it results in an image being progressively loaded (line by line) under the placeholder, which (for me) defeats the purpose of the placeholder.

Expected outcome

The original image should not be visible up until fully loaded, regardless of the placeholder.

Actual outcome

The original image is seen being progressively loaded (line by line) under the placeholder image.

Live Demo

https://jsbin.com/culezequje/1

Steps to reproduce

1. Open the JSBin.
2. Open the Chrome console and throttle your connection to something slower than 1mb/s, so you'll be able to see the original image being loaded (it's about 2.5 mb).
3. Make sure you also check "Disable cache", so the image won't come from the cache instantly.

Browsers Affected

• Chrome
• [?] Firefox
• [?] Safari 9
• [?] Safari 8
• [?] Safari 7
• [?] Edge
• [?] IE 11
• [?] IE 10