Overlong JPG displayed correctly by itself, in new tab: How? Options

[codecruncher]

Through observing and experimenting, I made the surprising (for me at least) discovery that an overlong JPG file on my website will (upon clicking) be shown in a new tab, and in a useful size - apparently if coded with its web address, rather than its internal address.

After the click/tab opening sequence completed, you will see the entire document from top to bottom filling the page, although much too small to read it (due to its size). Once you hover the pointer over it, a tooltip opens indicating that it will be magnified once you click. And it actually does, on top in a useful size. The only 'drawback' is that you now need to vertically scroll the file, to read all of it. A tiny inconvenience, given the reward, that I will gladly put up with.

I would have expected such a function under JavaScript or something (have no knowledge of these things), but no - it seems to be pure HTML. I can't find anything on the web with the search terms used by me.

Could anyone tell me what this function is called? I would like to read a bit more about it.

[codecruncher]

Well - it's a screengrab, as I announced. What else did you expect?

If you go back to the TO where I described the effect in detail, then just add the clip as an illustrating confirmation - wouldn't that do the trick? Of course, I would assume a basically constructive attitude

[pandy]

What else did you expect?

Something useful. For example you could answer my question and tell us what browser you use in the clip.