Which template are you using? If you’re using one of the default templates, those images will show right away. Only the templates that create the images on the fly have the loading effect, which then the above would apply. But if you’re using one of those templates and you have that many entries, I think you would better suited to use one that support paginated results.
Sorry, for rambling on, but I’m going to need a few more details before I can give a solution. Can you share a link to your directory?