How can one little checkbox cause so much pain?

For the past few months, off and on, I have been trying to figure out what the hell I could have done to my home version of Firefox that resulted in me not being able to see images on some web sites (like this one - I couldn't see the dots or images) but not all web sites. I uninstalled and reinstalled, that didn't help. I checked all the settings 867 times. I knew it was just me because I could see everything fine on Firefox at work.

Today I was determined to fix this thing so I went through each setting again, checking or unchecking boxes one by one until I found the culprit (oh, so I don't want to load images from the originating web site only).

Of course, now it makes perfect sense and I feel like a bit of a tool. At least I can also see all the navigation and images in Netflix, and I can remove the IE icon from my toolbar - both of which make me very happy.

THIS is why I'm not a programmer. You always want to know why, well - take it in.