When adding images to a page, are there copyright laws we need to consider when grabbing an image from the internet ?
Yes, there are. The copyright for most images is held by the photographer/designer/person who paid them to take it/create it, etc...and most folks don't take kindly to people using their stuff without permission. Also, please remember that copyright laws can vary from country to country.
That being said, there are always options. One of which is Creative Commons licensing. For example, there are a ton of images in flickr that have various Creative Commons licenses. Maybe you can find an image to use there (using only those that allow it and using it properly, of course).
Of course, I'm going to add to this our standard copyright answer:
It is the responsibility of the guide authors / library to determine if the content they're adding to their guides is copyright compliant.
If you have any question as to whether you should add someone's content to your page, you should look for a copyright statement on the content and/or on the site where it's shared, contact the copyright owner and ask permission to use/embed it in your guide, and/or consult your institution's / library's copyright expert or legal counsel before adding the content to your guide.