Why would you use JPEG, you heretic. JPEG has three use cases: photos (the kind you make with your digital camera or smartphone), situations where something else requires you to use JPEG, and memes about lossy image compression. ;)
It is explained how to use a custom contextual menu with a uiwebview <b>here</b>, but since we don't have a <b>UiWindow</b> we can't really catch the touch events before they are sent to the other views.
Implementing tabs seems kinda pointless if you can't use 'open-in new tab'.