Been using this free for some years. A bit of a PITA to use, but free. Mainly as a host for pics I want to show elsewhere. Like on say my car club forum. You just provide the link on there and the pic appears in the forum posting. But isn't actually recorded to the forum server. PB calls it third party hosting.
They've said that due to people avoiding reading ads on their site, they no longer get a viable income from them to pay for things. So now want 300 dollars a year to use this facility. (Before, you could go ad free for a few quid - so not quite sure where they get this figure from)