Image quality reduction & artifacts

I realise I am kinda picky, being a photographer I want my work to show clearly even if it isn’t a full-resolution image. Images were uploaded at 1920x1280, I am guessing the resizing has adding artifacts along high contrast edges as it sharpens.

snap.as: https://i.snap.as/C7CIafIQ.jpg
imgur: https://i.imgur.com/eOq6hPJ.jpg

I just realised I should try uploading an image I resized myself, so will try that before posting…
ok, so I set a custom size in Powertoys resizer to 1280x1280 and checked the images were clean after resizing.

aaand now it just makes it muddy. Still slight artifacting on edges. So not really an improvement.

I actually compared some vertical images that it doesn’t appear to resize (I assume it only cares about width) and noticed it actually just reduces takes out detail, I assume by reducing the quality setting of the converted image. And doesn’t actually reduce size of the file noticeably anyway. I export 1920x1280 90% quality jpegs at up to around 400KB, which I don’t consider excessive.

I am unsure if you can leave the quality as it is in the original image, I know when I use imagemagick convert to resize I enter the quality :thinking:

In the mean time I’ll host the files on imgur I guess, I like the detail in my images :slight_smile:

Not sure that snap.as was ever meant to host high resolution photos. My suggestion is to upload to Flickr or continue with imgur and just paste the link in your post. Write.as should auto detect the link and render it in a nice box.

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even when I resize below the minimum before uploading, it still introduces artifacts and reduces quality. I saw the snap.as post promoting it as a “you don’t need to rely on imgur anymore!” which is why I mentioned it. It’s not a deal-breaker for me at all, but if I don’t mention it then it will never get looked at, and at some point it probably should.

even if it’s a “image is below these dimensions and upload size, so leave it alone and just host the unchanged original image” type thing.

Hey, thanks for bringing this up, @swansinflight! It’s true we aren’t made for high-res photos yet, but this is definitely more of a bug – you shouldn’t have to rely on imgur when we have this service.

Looking at the code, we aren’t actually setting a JPEG quality value when re-encoding photos after resizing, so it’s likely just using some default (low) value, and creating those compression artifacts.

I’m not sure if we can detect an existing quality setting, but we can encode images at 95 or higher, and leave smaller images alone, and that should fix this. Will get a fix in soon.

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That would be awesome. :heart:

This is live now! Now JPEGs are re-encoded at 95 quality.

If you all still see issues / think this could be improved, please let us know!

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wooh speedy, thank you! Will test in next day or so.

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