Third-party image hosting trouble linking to wordpress gallery

I’m just starting to look at a third-party image host for my images on my gallery. I have started with Imageshack, but when I attempt to direct link the image, it doesn’t show the image.

I have been using the WordPress Media Upload to upload and store my images – however, now I’m concerned the number of images is becoming too great.

I’m using custom fields to link the images from the WordPress uploads folder, and have not had a problem. But to direct link from a third party source, it doesn’t seem to work. Any advice?