Whenever I open my Pictures app from the Media folder, it shows a link at the top that says "Explore Picture Apps" (which brings you to App World when you click on it.)
Uuuuuuh wtf is that, kinda weird for a service book to have such capability of modifying blackberry native apps interfaces. Either a service book or a cod file specific to your carrier's vendor id is causing that. You can try looking at which service book is named similar to that (pictures, explore pic, explorerimg, pictureexplorer, bbappworldpicture, whatever). But even if you delete the service book it will come back after a reboot. For the cod file is kinda annoying as you have to do a search in each alx the OS installation has for your carrier id number, which should be 126 to see the cods specific to your carrier.
Does it bring you to the main page of appworld or to the photo & video category?
Yee, it basically takes you to the photography category in app world. It looks like a browser shortcut that launches app world. Does it launch directly to that or you see first a white page then app world?
Mind posting your service books except the ones that contain your email address?
options > device > advanced system settings > service book