Unless specified otherwise, yes.
Yes.
Public domain images have no copyright restrictions.Creative Commons images are protected by copyright, but have extremely broad licenses.
No. In fact, the opposite is true. Most of the images you will find on Google® ARE protected by copyright which belongs to their respective owners.
Materials are not required to have a notification on them in order to be protected.
Photos online would be protected by copyright unless specifically stated otherwise.
Yes. There is no minimum age for copyright protection, and the images are automatically protected as soon as they are taken.
Video piracy is the act of copying video images and sound that are protected by a copyright, without the permission or consent of the copyright owner.
Copyright protected or trademark images, such as cartoon characters, require licenses from their owners.
Because works are automatically protected as soon as they are fixed in a tangible medium, you may assume that any video you encounter online is protected by copyright unless otherwise specified.
Any designs or images you paint must be your own original work, based on public domain images, or properly licensed. But the original images you paint are automatically protected by copyright for the rest of your life and then some.
No; all elements of Harper's Weekly are in the public domain.
You can use others' protected material if you have an exemption in the law or a license from the copyright holder.
No, but images (such as photos) of the paintings may be protected. Works of that period may also be protected by moral rights in some countries.