I have added images to a PDF and I have protected that PDF with password, so the only think, in theory, that I have authorized is printing.
Even so I open that PDF on Preview, click on any image, CMD C and CMD and I can copy that image easily.
I know that anyone can take a screnshot of that document and copy the images, but here is the point. The images are irregular and have transparency and they are over a background with an irregular pattern, so, if someone takes a screenshot will have a hell of a job to separate the stolen image from the background, so it can be used on other contexts. But if the image can be selected on Preview, copied and pasted, stealing the images are a piece of cake.
Yes, I have closed and opened the document, after protecting it. I am aware of this bug.
What kind of protection is this offered by Adobe Acrobat?
Best Answer
The entire suite of options within Adobe's PDF apps is pretty much optional to any other PDF-capable app. There's no way to truly lock a file.
Stack overflow has a list of ways to bypass protection -
How to remove security from a PDF file?
Another is 'just find an app that doesn't respect that particular aspect of protection'. You found one, Preview, there are many more.