As a novelist who has always resented the fact that my work can be purchased once and then loaned out forever by libraries or sold repeatedly by used book sellers without me ever seeing another darn dime for all the time, guts, heart, and sweat I pour into my work, I'm 100% with Richard's comments. Once I spend my hard-earned money on something, by gum, I should have the right to eat it, blow it to smithereens, cherish it forever, or sell it one time.
It's all a big mess, of course, with the modern digital versions of publications and books and music and films all too often available for free online if one knows where and/or how to look. As an example of what I mean by "big mess," in 2018 I created and then uploaded Kindle .mobi files of three of my novels to Amazon in a lame attempt to make a few bucks to pad the retirement check each month. While doing that, I noted with both amusement and annoyance, that used paperbacks of the first two of my novels from the late 80's were being sold for prices ranging from 38 cents to several hundred dollars. I priced the Kindle versions for $2.99, which was a buck cheaper than the original paperbacks. To date, I've made $112,680 from Amazon sales. Just kidding. In actuality, if I sell two copies a month, it's a good month. And I'd bet you a pitbull to a golden retriever that the Kindle versions are already available for free downloading in multiple places online. I don't like this, of course, but this is a reality of the digital world.
Here's another reality of our digital world that's happening every day on the internet. Getty Images is known for sending out demand for payment letters to website owners who have posted images they found online on their websites. The payment demands can range from a few hundred dollars to thousands of dollars for "copyright infringement." Now, let's say you have a magic blog read by 23 people during a good month and you innocently upload with one of your blog posts an image of David Blaine that you found on Google images. You don't think twice about doing this since there are literally thousands of images of David Blaine online. (As a side note "In 2014, according to Mary Meeker's annual Internet Trends report, people uploaded an average of 1.8 billion digital images every single day. That's 657 billion photos per year. Another way to think about it: Every two minutes, humans take more photos than ever existed in total 150 years ago." -- https://www.theatlantic.com/technology/archive/2015/11/how-many-photographs-of-you-are-out-there-in-the-world/413389/
NOW, get this... Getty has software that roams the internet 24/7 searching for images that it sells. If the software finds an image that Getty owns (or is the legal representative for the photographer who took the image) and the software doesn't find in its database a record of you purchasing a license to use that image, you're going to get from Getty an escalating series of letters threatening to sue if you don't pay an absurd amount of money because you have infringed a copyright. Though Getty has the legal right to demand payment for copyright infringement (if various conditions are met), many consider this to be a legal extortion scheme in a time of outdated copyright laws not suited for the digital age.
Now, here's where things get even more interesting...
BUT, if instead of downloading from Google images that image of David Blaine and then uploading the same image in your blog, you instead linked to that image (which is being hosted on another site), you are currently most likely not violating copyright according to...
... a recent case from the Ninth Circuit Court of Appeals concluded that inline linking does not directly infringe copyright because no copy is made on the site providing the link; the link is just HTML code pointing to the image or other material. See Perfect 10, Inc. v. Google, Inc., 508 F.3d 1146 (2007). Other courts may or may not follow this reasoning. However, the Ninth Circuit's decision is consistent with the majority of copyright linking cases which have found that linking, whether simple, deep, or inline, does not give rise to liability for copyright infringement. -- http://www.dmlp.org/legal-guide/linking-copyrighted-materials
Confused? Me too. Understanding copyright in the digital age is sometimes akin to trying to calculate the mass of the Milky Way galaxy in which we live -- which for those interested has recently been found to be about 1.5 trillion Suns' worth of mass (solar masses), within a radius of around 129,000 light-years.
To begin wrapping up what started out to be a simple comment about reselling digital media, I've given quite a bit of thought to all this and I have to admit that the only solution I've come up with to a hugely complicated mess is to dramatically change the status quo and simplify matters accordingly:
Now that we're in a digital age and now that some believe artificial intelligence will put most of us out of work in the next decade or so, it's time for a Universal Minimum Income of, say, $250,000 a year -- an income that will be adjusted up or down according to various statistical truths formulated each year by the AI that runs things. Copyright will become a thing of the past because since everyone will now have an income sufficient to live on, all of us can use our time to create stuff that's freely available to the world on the 'net.
Before anyone starts beefing about socialism and guaranteed incomes, many pundits suggest these daze that money is no longer money, anyway... that money in 2019 is merely electrical 1's and 0's that stream back and forth between central banks and governments and hedge fund managers and derivative gurus and the local supermarket via credit and/or debit cards and so on. Since first world money is now fundamentally digital, it has no inherent value: it can't be exchanged at Ft. Knox for gold or silver. At the same time, as long as nobody recognizes that money has no meaning or value anymore, then there's no reason not to give everyone a huge chunk of it every month so each of us can evolve into a creative person who creates all kinds of cool stuff to share with anyone with an interest and a computer or smartphone.
Just like magic!
What a wonderful world that would be, eh?