If I'm not mistaken, your talking about an image place holder.
Is this the icon you're referring to?
While waiting for the image, a placeholder for the image is created and the page continues to render.
When the image is downloaded it automatically replaces the placeholder.
You should be able to right click the icon, and select view image.
If you select properties, it will give you some information about the image.
If you have images blocked, you might also see this icon.
If it's this icon:
then the link to the image is broken, and you won't be able to view it, or it didn't fully load, in which case right clicking and selecting view, might bring it up.