In “Lesson 4: Chaining Asynchronous Requests” (or “Lesson 2” in the video; now our count is off by two!), there is a ridiculous claim that you cannot retrieve any photos beyond 4000 (or possibly less). That is pure nonsense!
Here is what the Flickr API is trying to tell you. Flickr is only going to return one page of results. If you do not ask for a particular page, you are going to get the default page (which is Page 1).
That page is going to have between zero and (the current maximum of) 500 results. (See `per_page` in the Flickr API documentation.) I believe at one time you could request up to 4000 results per page (hence the warning “Please note that Flickr will return at most the first 4,000 results for any given search query”), but that has since been reduced to 500. This does not limit you to only the first 500 (or even 4000) results though!
You can certainly request page 41 and receive valid results that are beyond the first 40 pages of 100 results each. I know this to be true, because my FlickrFinder app can and has done just that.
Is this because asking for a specific page is “a more specific query”? Yes, it is.
Maybe Flickr’s API was broken when the video for this lesson was made, but now it isn’t, so all of the discussion about 4000 and the limitations of retrieving photos is now obsolete. This line of code:
let pageLimit = min(totalPages, 40)
is completely unnecessary. Just use totalPages as the pageLimit.