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#1
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thumbnail sizes
I've been using this to make thumbnails of jpeg files:
for img in *.JPG; do echo thumbnailing $img convert -geometry 105x70 $img $img done Files from the K10D result in thumbnails of about 57 kB and those from the GR of about 46 kB, with little variation. Is there a simple explanation as to why? The K10D is 10 megapixels and the GR 16, but I don't see why that is relevant here, but maybe I am missing something. |
#2
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thumbnail sizes
"Phillip Helbig (undress to reply)" wrote
| I've been using this to make thumbnails of jpeg files: | | for img in *.JPG; do | echo thumbnailing $img | convert -geometry 105x70 $img $img | done | Are people supposed to know what OS/software you're using that code with? I wonder why you don't just extract the thumbnails when possible. Don't your cameras create them in the JPGs? It should be quicker and yield better quality images. |
#3
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thumbnail sizes
On 2018-01-07 21:46, Mayayana wrote:
"Phillip Helbig (undress to reply)" wrote | I've been using this to make thumbnails of jpeg files: | | for img in *.JPG; do | echo thumbnailing $img | convert -geometry 105x70 $img $img | done | Are people supposed to know what OS/software you're using that code with? Linux/bash and ImageMagick, obviously :-P I wonder why you don't just extract the thumbnails when possible. Don't your cameras create them in the JPGs? It should be quicker and yield better quality images. To customize the size and quality, for instance. -- Cheers, Carlos. |
#4
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thumbnail sizes
On Jan 7, 2018, Carlos E.R. wrote
(in article ): On 2018-01-07 21:46, Mayayana wrote: "Phillip Helbig (undress to wrote I've been using this to make thumbnails of jpeg files: for img in *.JPG; do echo thumbnailing $img convert -geometry 105x70 $img $img done Are people supposed to know what OS/software you're using that code with? Linux/bash and ImageMagick, obviously :-P That figures. I wonder why you don't just extract the thumbnails when possible. Don't your cameras create them in the JPGs? It should be quicker and yield better quality images. To customize the size and quality, for instance. Quality for thumbnails? To what purpose? It seems to be a waste of time, and a futile, unnecessary exercise. -- Regards, Savageduck |
#5
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thumbnail sizes
On 2018-01-07 22:26, Savageduck wrote:
On Jan 7, 2018, Carlos E.R. wrote (in article ): On 2018-01-07 21:46, Mayayana wrote: "Phillip Helbig (undress to wrote I've been using this to make thumbnails of jpeg files: for img in *.JPG; do echo thumbnailing $img convert -geometry 105x70 $img $img done Are people supposed to know what OS/software you're using that code with? Linux/bash and ImageMagick, obviously :-P That figures. I wonder why you don't just extract the thumbnails when possible. Don't your cameras create them in the JPGs? It should be quicker and yield better quality images. To customize the size and quality, for instance. Quality for thumbnails? To what purpose? It seems to be a waste of time, and a futile, unnecessary exercise. No. I said "to customize the size and quality" which is different than doing a quality thumbnail. ie, to have thumbnails of the exact quality (small quality) that one wishes. -- Cheers, Carlos. |
#6
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thumbnail sizes
On Jan 7, 2018, Carlos E.R. wrote
(in article ): On 2018-01-07 22:26, Savageduck wrote: On Jan 7, 2018, Carlos E.R. wrote (in article ): On 2018-01-07 21:46, Mayayana wrote: "Phillip Helbig (undress to wrote I've been using this to make thumbnails of jpeg files: for img in *.JPG; do echo thumbnailing $img convert -geometry 105x70 $img $img done Are people supposed to know what OS/software you're using that code with? Linux/bash and ImageMagick, obviously :-P That figures. I wonder why you don't just extract the thumbnails when possible. Don't your cameras create them in the JPGs? It should be quicker and yield better quality images. To customize the size and quality, for instance. Quality for thumbnails? To what purpose? It seems to be a waste of time, and a futile, unnecessary exercise. No. I said "to customize the size and quality" which is different than doing a quality thumbnail. ie, to have thumbnails of the exact quality (small quality) that one wishes. I am still baffled as why these thumbnails have to be produced in the first place. A proof/contact sheet, some sort of project, what? If there is some odd reason to produce them, which has yet to be explained, why would the concept of “quality” be attached to thumbnails of all things? I have been doing this digital photography thing for some time, and I have yet to have the need to produce a thumbnail of any quality. -- Regards, Savageduck |
#7
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thumbnail sizes
In article , Mayayana
wrote: | I've been using this to make thumbnails of jpeg files: | | for img in *.JPG; do | echo thumbnailing $img | convert -geometry 105x70 $img $img | done | Are people supposed to know what OS/software you're using that code with? yes I wonder why you don't just extract the thumbnails when possible. Don't your cameras create them in the JPGs? It should be quicker and yield better quality images. maybe he wants a different size. |
#8
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thumbnail sizes
In article , "Mayayana"
writes: | I've been using this to make thumbnails of jpeg files: | | for img in *.JPG; do | echo thumbnailing $img | convert -geometry 105x70 $img $img | done | Are people supposed to know what OS/software you're using that code with? No, but it shouldn't be necessary to get the gist of the above. I wonder why you don't just extract the thumbnails when possible. Don't your cameras create them in the JPGs? It should be quicker and yield better quality images. Maybe they do; I don't know. How can I check. For the same size, why should they be better quality? |
#9
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thumbnail sizes
On 2018-01-07 21:07, Phillip Helbig (undress to reply) wrote:
I've been using this to make thumbnails of jpeg files: for img in *.JPG; do echo thumbnailing $img convert -geometry 105x70 $img $img done Files from the K10D result in thumbnails of about 57 kB and those from the GR of about 46 kB, with little variation. Is there a simple explanation as to why? The K10D is 10 megapixels and the GR 16, but I don't see why that is relevant here, but maybe I am missing something. I was going to say that the camera with more megapixels would convert to a bigger size, but the reverse is happening. -- Cheers, Carlos. |
#10
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thumbnail sizes
"Carlos E.R." wrote
| I was going to say that the camera with more megapixels would convert to | a bigger size, but the reverse is happening. | MP doesn't matter because it's the same number of pixels in the thumbnail if they're both the same width/height. There could be slight differences due to simpler or more complex images that compress differently, but with such a big difference the only explanation I can think of is that there's a difference in the compression. The code doesn't include a "quality" parameter to set compression level so maybe ImageMagick is deciding based on input size? Who knows? He's using a hammer to hit a tack. It's hard to see why it should matter. He's using a limited command line tool to get thumbnails and not even setting the quality option. Does he really need exactly that size? If so, why? Is it worth sacrificing quality? He didn't explain any of that. Apparently he doesn't care very much about the quality but is just curious about the different file sizes resulting. |
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