You can create links by adding rel="nofollow" tag, which is not searched by search engines. You also should add nofollow tag to the links, you think it doesn't need it.
The links on the other websites are called external link.
You should not have too much external links on your website.
Other wise this will affects your website negatively.
It's very important to use pictures on your website to bring up the main concepts of your website. Search engines understand the pictures by their alt tags.
If there is no alt tag, search engine doesn't understand anything from the image.
That's why you should use alt tag on your all pictures, which you use in your website.