I'm sorry that I didn't see this comment earlier @rouketas, but as you didn't tag me properly (purposely or not), I'm aware of it just now, when another user drow my attention to it.

But to answer your "pointing finger" comment...
In all my posts (or at least 99% of them), including the first ones, I'm using my own photos or the photos from Pixabay.com (which are under the CC0 Creative Commons license, free for commercial use and with NO attribution required).

Therefore, and just for your information, I didn't need and I don't need to put a source for any of these! (Although, now and for quite some time by now I'm doing that even for them too, just because of those people who don't care for someone else's authors rights.) When I use other sources (if they are free to use and free to use for commercial purposes) I give a proper attribution.

Accordingly, the post you've linked to contains the photos, images and/or illustrations from Pixabay.com, some of which I changed, by that creating my own derivative work (what I'm also allowed to do with Pixabay photos) for the purpose of my article.

The same applies even to the (arrow) GIF as it's, in fact, my own creation. This GIF is created with several images and illustration from Pixabay. Again, my own derivative work!

And last, but not least, for "smart ones" as you apparently wanted to be, and just in case, I keep the records for every single source that I have ever used (no matter if for my online or offline publishing).

So, to conclude...
My dear finger pointer, who didn't do your research well or even at all, you pointed your finger at the wrong direction!!!

P.S. (edited)
And now, also seeing @annaabi's reply to you, it seems it wasn't only a wrong direction, it was in fact wrong directionS!!!