Category talk:Images with excessive JPEG compression

Image

I suggest to remove the double donkey image... It does not help to understand the problem. -- Basilicofresco (msg) 06:54, 18 March 2013 (UTC)

What images should be tagged with this?

These IMHO should not be tagged with this:

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  Doesn't seem overcompressed, it's just noisy which jpg doesn't like

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  Not really bad enough to justify being here

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  low resolution but not particularly overcompressed

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  issues not related to compression

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  not that bad

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  why is this here

That's the problem with templates/categories like this: they attract images for no reason or the wrong reason because people don't know what compression is. - Alexis Jazz ^{ping plz} 13:51, 20 October 2018 (UTC)

Hey Alexis Jazz, you are right, low resolution, blurred or general low quality is not subject of this template. Let us say this is a sub-part of the Category:Images of low quality. But the image: Estasi di Santa Teresa.jpg I would be let here, as noise is a result of over-compressing too, compare: File:JPEG Generation Loss rotating 90 (stitch of 0,100,200,500,900,2000 times).png -- User: Perhelion 14:31, 20 October 2018 (UTC)

@Perhelion: I don't believe that's the case here. The camera made a noisy picture (wrong settings, not enough light). Jpg artifacts on noisy pictures are more visible, but that's not due to overcompression. - Alexis Jazz ^{ping plz} 15:21, 20 October 2018 (UTC)

Maybe a mix, but we can see square patterns, which is a clear sign of compression not that noise from a camera, IMHO. So may you could tag this as Template:Regular noise too. -- User: Perhelion 19:21, 20 October 2018 (UTC)

@Noise: e.g. File:Bruce's Green Pigeon - Gambia (32495702332).jpg looks more at noise as the controversial claimed example before. But there is no camera noise at this photo (very unlikely on sky), it is re-compressed over hundred times (shown with ExifTool as Adobe edits). -- User: Perhelion 12:00, 21 October 2018 (UTC)

@Perhelion: the original (first revision) doesn't seem to have been re-compressed many times and looks the same in terms of compression. - Alexis Jazz ^{ping plz} 12:18, 21 October 2018 (UTC)

Anyway my point was.. I would suggest to use {{Overcompressed JPEG}} only for the most egregious examples like File:Ft Clatsop Oct2001.jpg and potentially files that have some hope of being fixed (better version available from the source, recently uploaded own work, artifacts that could be photoshopped away). I don't see the point of including files like File:Bruce's Green Pigeon - Gambia (32495702332).jpg here, you could tag millions of files if that's the threshold. - Alexis Jazz ^{ping plz} 13:24, 21 October 2018 (UTC)

Yes, you are right! (this Exif-info was claimed by the editor itself[1]) -- User: Perhelion 20:20, 21 October 2018 (UTC)

Unbeknownst of the discussion, removed Estasi_di_Santa_Teresa.jpg (just noisy) – certainly not a compression level problem. Incnis Mrsi (talk) 11:41, 18 December 2018 (UTC)

Images from Geograph Britain and Ireland

Of the first 1500 images there, I found more than 80 grossly overcompressed pictures. Given that the category contains ∼ 1.8M images—that is, 1200 times more than already reviewed—we can expect about 100k new members. Obviously, a new category is necessary, but it raises two more questions:

1. How to find especially bad pictures (except for manually)?
2. Would it be wise to use the same {{Overcompressed JPEG}} (albeit with a special parameter for redefinition of category), or alternatively we should implement a special parameter in {{Geograph}}?

Incnis Mrsi (talk) 05:39, 18 May 2019 (UTC)