If your use would not be considered fair, ask the copyright holder for permission, in writing, and be specific.
It might be because of copyright violations. The image might be subject to copyright. You have to use your image only as the profile picture.
The content of a presentation is protected by copyright as soon as it is "fixed."
If the presentation would qualify under the "fair use" exception (see link below) then yes you could use them.
It depends on the nature of the presentation, and how the images fit in. If the use of the images is transformative, that would be covered under copyright law (for example, if your presentation is for educational purposes, and is discussing use of color in corporate logos, including the logos would be defensible under fair use). But using an unlicensed stock photo of a man breaking a pencil to illustrate a presentation on workplace stress is likely to be found to be infringing.
It depends on the context of the image in the presentation. For example, if your presentation is about online auction services, your use of the eBay logo would be defensible under fair use.
Copyright is very important. It is in place because if you made a picture of example, you want people to know that it is what you have created. By using copyright any one who would like to use this picture/ design, etc will need your permission. As it is there design, you can't 'nick' it.
The picture itself is protected by copyright; downloading it without permission would be copyright infringement.
The copyright status of a guardian angel picture depends on who created it and when it was made. Generally, artworks remain protected under copyright law for the creator's life plus 70 years. If the picture is in the public domain, it means that its copyright has expired or the creator has waived their rights, allowing anyone to use it freely. It is best to research the specific picture's copyright status to determine if it is in the public domain.
They copyright the picture which makes it their "property". If you want to use their picture (property), you have to pay to get one without their name on it.
Unless if your report would qualify under the "fair use" exception your next step is to contact the copyright holder for permission to use the photograph.
Dozens, if not hundreds. Every time you create something new, it is automatically protected by copyright. Doodle a picture of a cat, you have copyright. Take a picture with your phone, you have copyright. Record yourself making up a song, you have copyright.
Simply writing the word, no.