Screenshot resolution inverse to web page zoom level

[dirrgang]

It seems like there has recently been introduced a bug to the screenshot feature of Firefox.

I had noticed that the resolution of the screenshot was lower than it had been in the past. I've discussed the issue on reddit and /u/aplaice has done some digging:

Yes, you're right. It seems that the width of the screenshots is now being scaled down inversely to the magnification (so if you have a magnification of 200 %, the width, in pixels, will be half of what it was at 100 %, and unfortunately the resolution per pixel will be the same). (Conversely, if you zoom out in Firefox and take a screenshot, the image will be "sharper" than displayed within Firefox.) Presumably the screenshot width is now based on viewport width, not on original screen width.

This is obviously not how zoom works when you're viewing a webpage within firefox — webpages don't get more blurry when you zoom in. Since, there's a mismatch between what's viewed on screen and what's screenshotted, it definitely seems to be a bug, so report it!

There has been a similar issue (#4174) but unlike that one it seems to be primarily caused by zoom levels of the webpage and not the DPI/UI scaling.