How big was the Tonga eruption?

Re:How big was the Tonga eruption? by lelandbatey on Monday January 24, 2022 @01:18PM (#30061591)

Yes, they did use transparent shadows. You can tell because the images are not GIF's, they're actually a sequence of PNG images overlayed atop other PNG images. There's the base satellite image of the area, then the frames-of-explosion-with-transparency overlayed atop them. You can confirm this by right clicking on the image and choosing "open image in new tab", which will (usually) open this final frame in a new tab.

[0] - https://graphics.reuters.com/TONGA-VOLCANO/lgpdwjyqbvo/cdn/i...

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Re:How big was the Tonga eruption? by bt1a on Monday January 24, 2022 @02:32PM (#30062718)

I tried to save one of the "gifs" to share with a friend and was quite upset that I found myself with a png. Interesting technique. Do you think this was done to have better quality animated images? GIF compression isn't amazing (relative to WebM at least)

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Re:How big was the Tonga eruption? by jameshart on Monday January 24, 2022 @04:25PM (#30064258)

Very gratified they didn’t just post these as rendered gifs.

Imagine the social media scare you could generate in a year or so after everyone has forgotten about this eruption by sharing a graphics.reuters.com URL for one of these animations that appears to show a satellite image sequence of a massive mushroom cloud obliterating the Korean Peninsula or the Sinai with a breathless ‘LOOK WHAT REUTERS JUST REPORTED!!!’ caption.

It’s really important for reputable sources posting images to think about the fake news potential of them getting shared out of context.

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Re:How big was the Tonga eruption? by capitainenemo on Monday January 24, 2022 @03:04PM (#30063212)

I mean, they could have used APNG at this point. https://caniuse.com/apng

Doesn't compress stuff like that super well but no worse than a sequence of PNGs.

I feel if you're gonna use JS animation anyway, you could just use 2 jpegs, one for masking and a canvas.

Hm. Webp is doing darn well these days too. https://caniuse.com/webp

Avif isn't an option yet.

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Re:How big was the Tonga eruption? by dylan604 on Monday January 24, 2022 @03:07PM (#30063245)

Probably more along the line of they have some library that uses PNG sequences. Maybe even as simple as a slideshow with short durations. It's a newsy site. They don't have a lot of control over what their CMS/publishing platform can do. Someone probably had a clever idea on how to use something existing in a way not envisioned when created.

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