A tip for everybody.
When you upload your own pics, put a watermark in your image if you don't want others using them. Most modern image software programs include a pretty easy-to-use watermarking process.
If you don't have an image processor you can get something like
Imagemagick free of charge, or even create an online watermark at a site like
Picmarkr.
If you see a pic online that you like, I've found simply asking the creator to use it often results in a yes.
