Tinypic can be very slow to load images to your screen and it seems that the site simply gives up trying if (presumably due to heavy traffic) it can't achieve the task within a short space of time.
Hostingpics is far, far better. (There's no annoying 'Captcha' thingy to negotiate when uploading, for a start):
http://www.hostingpics.net/
To upload an image, click the top 'Browse' button.
Navigate to your image file and double-click on it.
Click 'Envoyer'.
Ignore the links which appear. Simply click on the thumbnail to see a larger image framed by the Hostingpics background.
Click again on that image to get to a window containing nothing but the image.
Copy the URL and paste it into an AB post.