Very nice Tomasz. Congratulations on a lovely piece of work.
Hopefully, now is the time for some serious playing!
Stay safe,
Nick
PS, I use Google dropbox for posting images. There is a mechanism by which you can easily create a 'shareable link' for any images in it. they look like this ' https://drive.google.com/open?id=0B7clI ... kE2SXl2WDQ ' but if you try and use that link 'as is' it will generate the error you describe. Somehow, I came across the solution which is to change the link to ' https://drive.google.com/uc?id=0B7clI8_ ... kE2SXl2WDQ ' (that is, change ' open? ' into ' uc?' ). If you then put the modified link between the image tags it seems to work. Possibly, there is a similar problem (and similarly obscure solution) with Flickr.