You will use the QuickCite option to copy and paste the citation from Britannica ImageQuest into NoodleTools (look for the little check mark when you open the image in ImageQuest).
Google-Filtered Image Search
If you cannot find the images you need on Britannica ImageQuest, you can search the web. Just know that you must filter your search to find the images you have been granted permission to use (not all of the images online are free for you to use!).
On this Google Doc are directions on how to search the web and filter your search results so that the images you find are the ones you are allowed to use in a project. The directions also include how to cite from a website.