OK, I can't answer WHY certain things happen on the internet, but I can guess about why they MIGHT happen. If Photobucket has slow loading times, which does happen when it is experiencing high usage, it will cause some users to have slow page loading problems when graphics and/or images are linked to them.
The reason it does not affect ALL users, is some people leave their cache size at half of their hard drive size, meaning they could have terrabytes of images stored locally and don't have to wait for the image to load from the online source each time the page is opened. I won't go into the good and bad of doing that, but you can see how different local settings can afftect your page.
You don't have to be anywhere near a computer for other people to experience intermittent issues with your page. Try removing the Photobucket images for a day and see if your slow pages speed up. If they do, look for some domain space to store your images. You can get domain space for under $10 a year to register and $10 a month for the space. If you need help doing that, let me know. I maintain about 2 dozen websites.
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