A couple of years ago I went on a trip to Barcelona and posted some pictures, including a panorama of the Sagrada Familia church:
That picture ended up in Google image search among others and lots of non-technical bloggers seem to have chosen to use it if they want a picture from Barcelona. The only problem is that they don’t save it to their own website, they link to the copy on my site.
To make matters worse they usually display it at thumbnail size by telling the browser to resize it. So what happens is that the end-user’s browser downloads a huge picture and then resizes it to show it on the screen. This download comes from my web host and uses up bandwidth, which is a finite resource and costs money if I use too much.
OK, non-technical people might not realise the problem, so I usually try to contact them and suggest that they use the thumbnail-size version instead. Most of them ignore me.
What is really annoying and has nothing to do with technical knowledge is that most of them don’t even credit me. They use my picture and then effectively pass it off as their own. On the right-hand side of these pages is a little copyright notice. In general I’m happy for people to use my pictures but you must ask me or you’re breaking copyright law.