Some images disappear in Safari after page loads

On some webpages, there's a problem with Safari showing images. For a brief second, the image appears and then a blue question mark inside a blank square appears where the image had been. When I load the same webpage with Firefox the image shows without a problem. I've disabled the few extensions I'm running in Safari to no avail. Again, with or without extensions, Firefox displays properly (they're both using the same extensions). I'm using Yosemite 10.10.2 with Safari 8.0.4. Any thoughts would be greatly appreciated. Thanks!