What do you mean by "not appearing"? Not appearing in the post list? Not appearing under a specific tag? Or the image doesn't appear when you view the post? Be more specific...
If you can't see the image I would recommend doing a hard refresh. Sometimes your browser will fail to load an image and then that failed image is cached so no matter how many times you refresh it's still not visible. In that case you have to do a hard refresh by hitting Ctrl + F5.
Also I see you are viewing the website through https instead of http...which I've had some issues with in the past...switch over to http and it might work better:
rule34.xxx/index.php?page=post&s=view&id=2450106