When I load my site up in IE (I'm using 8 but I've seen this happen on 7 and 6 too) every now any then it will show the "red x" for some images. I know those images exist so I refresh the page. When it renders again those images that had a "red x" are now displaying properly, but other images, even ones that were displaying properly in the last render, now have a "red x".
I usually need to refresh a handful of times before it renders the entire page properly.
I don't know what causes this or how to repeat it.
I did take a look at the network traffic in Firefox and noticed most of the images were coming back 403 Not Modified.
Has anyone else experienced this? Do you know any way of fixing it?