I've clicked the message at the top of the screen that pops up that notifies that the image has been resized and can be shown in it's original size. Now I regret this choice. Can I reset this? I've searched the profile options and see nothing.

I'm not sure I understand your issue...

Viewing original image is on a per-image basis. Can you link me to the image that you first clicked "show original image" on? We'll go from there.

Alaron, he selected 'Always view original', he wants to revert that.

I thought it's some elaborate error...

Just clear the cookies of your browser. Should fix it.