i have been using
tinyPicevery since imageshack decided to change their contract and not allow [img] tags to link to their pictures.
its 100% free
you need to register to make it work
but if you register, you get a few extra options and some management of your folders
im sure theres some extra bonuses for paying customers, but i never looked into those.
im not sure about privacy limitations with this host, but tbh i dont really care. they cant do anything that will harm me with the pictures i host there, most of them are just status report and asking for help pictures of my cars.
Ideally i would be using a host service that would allow me to FTP transfer my files usinf filezilla, since sometimes uploading 20-50 pictures in 1 go with batches of 5 is really tedious.