The long version: The original images are not protected by copyright, that has long expired. However, as with most legal questions, there are other factors to consider.
While the originals may be public domain if any editing or enhancements have been done to the photos (cropping, contrast/brightness adjustments, etc) the rights to those changes would, in all likelihood, belong to Harpers Weekly. Additionally the arrangement of the photos and any accompanying text, provided it qualifies as copyrightable, would also be protected.
The short version: No you probably can't "help yourself" to the photos & use them without permission.
No; all elements of Harper's Weekly are in the public domain.
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.
Unless specified otherwise, yes.
Materials are not required to have a notification on them in order to be protected.
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.
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.
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.
The name cannot be protected by copyright, and has not been registered as a trademark, although common-law trademark would be respected as it has been used in commerce for some time. Images and other content supplied by Boss Chicks would be protected by copyright.