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Is it possibly to force zoomable images to be downloaded as lossless (eg png) without manually specifying a file name?

Open BrokenBrainiac opened this issue 5 months ago • 1 comments

I don't see a command line argument for this. This would be especially useful with combined with the new bulk download ability.

When I feed a url from Google Arts into dezoomify, I get a jpeg with a descriptive filename eg "Ricci, Sebastiano; City Surrenders; 1686-1688.jpg"; it is annoying to have to manually specify filenames if I wish to retrieve images in a lossless format like Png. Dezoomify isn't currently able to losslessly combine the original jpeg tiles (it sounds very tricky to do programmatically). In the past, images downloaded at default setting with dezoomify were saved at jpeg quality 80 (no chroma subsampling); today I am getting quality 95 with no subsampling. The actual tiles on Google, for the painting I was looking at, were compressed at jpeg 88 with chroma subsampling (I'm not sure if that is the case for all Google Arts; and different sites use different compression settings for the jpeg tiles). With a png, I have the option to manually compress at whatever setting I like using whatever codec I like (codec resolution limits are still there though).

So, essentially an argument like -ll or -png to force lossless is what I would like.

Thank you Lovasoa for creating and supporting this very useful specialist program. I sometimes see HQ versions of public domain images on Wiki Commons that were downloaded using this software. Public domain means they belong to all of us; they are part of our cultural heritage.

BrokenBrainiac avatar Jul 09 '25 15:07 BrokenBrainiac

O my brother

I don't see a command line argument for this. This would be especially useful with combined with the new bulk download ability.

When I feed a url from Google Arts into dezoomify, I get a jpeg with a descriptive filename eg "Ricci, Sebastiano; City Surrenders; 1686-1688.jpg"; it is annoying to have to manually specify filenames if I wish to retrieve images in a lossless format like Png. Dezoomify isn't currently able to losslessly combine the original jpeg tiles (it sounds very tricky to do programmatically). In the past, images downloaded at default setting with dezoomify were saved at jpeg quality 80 (no chroma subsampling); today I am getting quality 95 with no subsampling. The actual tiles on Google, for the painting I was looking at, were compressed at jpeg 88 with chroma subsampling (I'm not sure if that is the case for all Google Arts; and different sites use different compression settings for the jpeg tiles). With a png, I have the option to manually compress at whatever setting I like using whatever codec I like (codec resolution limits are still there though).

So, essentially an argument like -ll or -png to force lossless is what I would like.

Thank you Lovasoa for creating and supporting this very useful specialist program. I sometimes see HQ versions of public domain images on Wiki Commons that were downloaded using this software. Public domain means they belong to all of us; they are part of our cultural heritage.

O my brother, what you are asking is true, but bear in mind this is a free to use software with voluntary donations, We have no right to ask Ophir anything before we contribute. Brother Ophir is doing god's work here O my droogie. So maybe before throwing your demands at him let's all donate to this noble cause. I am not saying you were being rude or something but it takes guts and lot of intelligence to create something like this. So please O my dear brothers and sisters to whomsoever this may concern. Please donate so that ophir can continue to run dezoomify smooooothly.