Adding this template to lots of pages isn't helpful. It's better to have no image at all than this prominent, oversized and blurry non-image with a Wikipedia-style "This page needs..." underneath. The randomized tips in the editnotice include "People who edit make up just over 1% of all traffic. That is, about 99% of traffic comes from non-editing readers. Try to keep this in mind when editing." Adding something to a page that is directed only at editors does nothing for readers, and if it's something like this, it's likely to turn them off. It's also likely to turn off editors rather than encourage them to add images. I don't recall seeing any instances of this template replaced with images, and it can stay on for years. (Those three examples are all taken from the first page of Category:Pages Needing Images. I expect there are many more.)
Wikipedia's notorious orange boxes actually look better than this. They're not overly large, they don't push the content over, they have a nice color and layout scheme that harmonizes with other templates, and they use descriptive, clean-looking vector icons instead of a raster image of a red X that is obviously scaled up too far. This template could be more aesthetic and discreet, but it's not. If it's really necessary to have a list of "pages needing images", it would be preferable to use only the category. This makes it easy for editors to locate these pages while not getting in the way of the readers' experience.