Questions tagged [image-compression]

Image compression comprise methods with the goal to reduce the size of an image by either removing redundant or less important information (or a combination of the two).

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3answers
99 views

why won't my photos compress past a certain size?

I'm having issues compressing my film scans to a suitable size for use on my website. for example, I have a .jpg file with a size of 17.4 MB. I opened the photo in Photoshop and tried two methods: ...
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2answers
69 views

How to determine which jpeg is closer to the original image and has the most information?

I've got two jpegs of the same photo of different sizes and attributes. How can I tell if one is the original taken by an iPhone4 or if neither is the original, determine which has the most ...
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4answers
271 views

Best storage for photos without compression of photos or videos on server

I am using google drive as of now for storing the pictures. I have pictures which is of 26 mp so google drive is compressing and removing the quality of pictures. Is there any other storage quality ...
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2answers
78 views

Batch Compress and Watermark Images?

I am building a website for a client, and he needs some software to be able to add watermarks too, and slightly compress for bandwidth on his website. I'm struggling to find a solution that does both ...
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2answers
264 views

How can I simulate JPEG quality degradation? [duplicate]

I am writing a report about file formats in images & their properties. In the report I want to talk about how file formats have lossy compression rather than lossless compression & I wanted to ...
2
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0answers
191 views

Why aren't dct quantization tables symmetrical [closed]

Many image compression standards use the DCT transform to convert spacial data into frequency data. The DCT coefficents are then quantized based on the estimated importance of a certain frequency to ...
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1answer
315 views

What are Olympus' best in-camera Jpg settings for facebook

I usually shoot raw and make minimal in-camera post-processing with my O-M10 Mark II before exporting the photos to Facebook. Did anyone figure out what are the best in-camera jpeg resolution and ...
21
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2answers
5k views

Google Photos high quality backup — how does Google achieve great compression and am I losing some data?

I'm sure that many of us have used Google photos high quality backup which allows us to store photos online without fees. Recently, I thought of testing just how high quality the uploads really were ...
29
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4answers
5k views

What factors cause or prevent “generational loss” when JPEGs are recompressed multiple times?

For years, I've believed that recompressing JPEG files multiple times would gradually degrade its quality until they are an unrecognizable mess, the way making photocopies of photocopies does. This ...
3
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1answer
241 views

Should I resize photos before or after image optimization?

I am a software dev who appreciates stunning imagry in sites I build, but am also very conscious of page size. My workflow has me adjusting image sizes to the maximum resolution they will be displayed ...
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1answer
100 views

regarding image transfer [closed]

I have this client that is having a very frustrating time. I took some pictures for their clothing line. I formatted them for social media posting and copied them to a USB. I gave her the USB and for ...
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4answers
7k views

Is it not ideal to save image as PNG for printing?

So the scenario: I want to order a print of one of my images. It is a special image and will be relatively large (a couple of metres) so I want it to be perfect as possible. I have the RAW file, ...
4
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2answers
2k views

Why are JPEG images from camera huge and the same images exported from Vistaprint software 10 times smaller?

JPEG images from my Nikon D3300 are roughly 12-15MB big at 6000 x 4000resolution. RAW images converted to JPEG through LightRoom are also 12-16 MB. I recently created an album through VistaPrint ...
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3answers
714 views

Is it possible for jpg images of the same source have different file sizes but the same quality?

I have been using Google Photos as a way of backing up my photos. I noticed recently that they store two versions of any photo I upload, one with the original name of the file, say, IMG_20140328_1143....
4
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5answers
3k views

What is difference between 8bit RGB and 16bit RGB?

Most of time when I open any images to Photoshop, it shows 8bit RGB format, but I have also seen 16bit RGB. As a trial, I copied one image and pasted it into a 16bit RGB blank image, but I didn't get ...
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2answers
2k views

Is it possible to find out what compression ratio was used for a particular JPEG?

I have a couple of JPEGs. Is there a way to find out which compression level was used when encoding them? That is, were they encoded at level 60 or 90? The reason I'm asking is because I have a site ...
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1answer
248 views

Strange image artefacts from PS3 Eye camera

I am using PS3 Eye camera (model 5SLEH-00448) to take photos with OpenCV (C++) on Rapsberry Pi. It runs via v4l2 driver that only supports YUYV uncompressed capture mode. I save the images as PNG. I ...
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1answer
1k views

How to compress an image to a particular size in jpeg regardless of quality?

Scenario: I have an android app which captures images and sends over to a server. Till now I had been setting 50% quality. But with high end phones with better sensors and resolutions even with that ...
1
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1answer
88 views

If the image is B&W can i make it 12mp and 300dpi in lightroom? [duplicate]

Hello soo im having a problem, i shot in raw a picture for a contest, days ago i asked a question about this. However, now that I finally took the shot and it was in B&W with the camera and also ...
0
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1answer
85 views

How do Adobe Smart Previews work?

I've always been under the impression that you cannot resize a raw image. Adobe Smart Previews seem to do just that - you keep all the power of raw images, just in a much smaller size. How does this ...
4
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3answers
1k views

Quality of JPEG directly from RAW+JPEG versus JPEG embedded in RAW of RAW+JPEG?

When I use ImageMagick's identify command to look at the quality of the JPEG from my camera's RAW+JPEG mode, I see 95. When I use the same to look at the JPEG preview that has been directly extracted ...
1
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1answer
255 views

Remove “random” noise [closed]

I have a picture which was taken from a book and it's full of noise: I tried to remove the noise manually but it is too difficult and takes a lot of time. I noticed some webpages who attempt to treat ...
0
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2answers
100 views

Do some colors appear more sensitive to chrominance perceived than others?

I'm interested in comparing the camera readable chrominance change to what a person can actually see. Are there any colors that result in a physical / measurable change in chrominance, but are ...
0
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1answer
378 views

Compressing photos using Microsoft Picture Manager?

I have a number of photo's which are >7mb in size and I want to upload them online for a photobook. I have uploaded photo's of this size to numerous photobook sites before but this particular site for ...
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2answers
914 views

Which is the best strategy to downsize an image file?

Images created by a camera or by a scanner can get a very large file size. this huge size has downsides: Can't send over mail. Can't publish on a web site Any action abuses the computer CPU and ...
0
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3answers
781 views

How do I compress my TIFF files to JPEGs of a given size?

An online lab wants my large (over 100 MB) TIFF files as 50 MB JPEGs with a maximum of 80 megapixels for making aluminum 16x24 inch prints. What about final resolution? How do I convert from one to ...
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2answers
3k views

How to increase/decrease image size without changing dimensions or dpi

I have 50 photos with different size from 50 KB to 70 KB. I want all photos tobe in 60-70 KB size without changing the dimensions, dpi, or bit depth.
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7answers
832 views

Compress a few small areas of an image in higher quality

I would like to prepare a photo to display it on a webpage. I would like to compress this image such that most of the image is compressed to lower quality, to reduce download size, but a few small ...
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2answers
587 views

Why doesn't PNG show more detail than JPEG in a converted NASA image?

I have a really limited knowledge of photography, so, bearing that in mind, here is my problem. I downloaded an IMG file with a separate label file from NASA PDS because I wanted to visualise the ...
2
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3answers
339 views

Lossy but essential: is there a modern file format useful for modern camera files?

I remember the early digital cameras that had anything resembling useful quality (megapixel) stored JPEG files that were noticeably lossy. As memory cards became more capable, this was addressed and ...
5
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1answer
1k views

Does writing EXIF tags influence jpeg quality?

If I understand well then the EXIF data is written in an extra space of the JPEG file. When I add or modify an EXIF tag does this leave the picture untouched? I searched for this and I was not able to ...
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2answers
197 views

Is there an easy way to export photos from Lightroom in original format if they're unedited?

When I export a folder or collection from Lightroom, I want unedited photos exported in their original format (like DNG, ARW, PNG) and edited photos exported in a chosen format, like JPEG. Is there ...
3
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1answer
495 views

What are the anomalies in this picture of earth?

I was playing around with the New NASA pic of earth (posted July 20th 2015 on Nasa Goddard space flight center on Flickr). I've found this very odd structure on the bottom right corner that is pretty ...
13
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3answers
4k views

Is there a lossy compressed file format for 16-bit dynamic range images?

I'd like to aggressively compress some scientific 16-bit grayscale image files, but without reducing the dynamic range. Is such a thing possible? I understand that JPEG format uses lossy, and ...
3
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1answer
521 views

What is the relationship between ARW delta compression and dynamic range?

I read this article about the fact that Sony AWR is not a lossless RAW format, but, rather, an 11-bit + 7 delta compression. According to DXOmark, the dynamic range of A7r is 14.1, as opposed to 14....
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1answer
667 views

Enable TIFF compression in Canon Digital Photo Professional 4

I can't find a way to enable TIFF compression in the files produced by batch export in Canon Digital Photo Professional (currently version 4.2). This means that the generated TIFF files are far larger ...
3
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4answers
601 views

Why do modern DSLRs support JPEG but not lossless formats other than RAW?

I'm from a programming background and very new to photography. While working with the SDK for the Canon Rebel T3i, I realized that the only image formats natively supported by the camera are RAW (CR2) ...
2
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5answers
3k views

What is the real world impact of the lossy compression used for NEF RAW files in some Nikon cameras?

I intend on buying a DSLR in the near future and my eye has been stuck on the Nikon D5300. One of the things in photography that I feel uncomfortable with is compression, therefore I obviously care ...
2
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4answers
558 views

What is the best practice for batch compressing jpeg files?

This is fairly theoretical, as it is definitely in the realm of "pixel peeping" and is more or less irrelevant for practical use, but with the increasing popularity of full-width images on websites, I'...
4
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4answers
5k views

Best program to batch compress JPGs with minimal loss?

My photo catalog is getting bigger and bigger. It's mainly my fault because in my noob years I used to export all JPGs with a 100% quality, point at which files can reach the 10mb mark or even more. I ...
6
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2answers
2k views

How does the usual jpeg 0-100 quality settings translate into Photoshop's 0-12 quality setting?

JPEG encoders usually use a quality setting of 0-100, whereas Adobe photo software uses a 0-12 setting. Does anyone know how to convert between these? (I am actually not clear on whether the 0-100 ...
24
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12answers
37k views

Does simply opening and closing a JPEG file decrease image quality?

I've had quite a few photography classes, read many photography books, and screened many forums. And I can't find a consistent answer to this question. One "camp" says there is a loss of image quality ...
2
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1answer
355 views

If PNG is Lossless Why Does Difference Blending Mode Show a Difference

I often read that PNG is a lossless format so I decided to do a little experiment to try to prove it. In Photoshop I did Save for Web to PNG-24. Then, I did File->Place to open the PNG and import it ...
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1answer
192 views

2 Versions of a Photo: Same resolution, image diff shows no difference, but different filesize

I have two versions of a JPG photo. According to the metadata, one has been saved in Shotwell while the other one is probably the orginal. Both files have the same resolution, dpi, bit depth, color ...
2
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2answers
733 views

Does a JPEG image uncompressed to bitmap prior to displaying it on the screen [closed]

Does a JPEG image converted back to bitmap image when displayed on the screen? Does it occupy more memory than the actual file-size when it is being displayed? Does JPEG images, if added to the web-...
7
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3answers
3k views

Make photos on Facebook nicer?

I upload photos to my Facebook page using the latest Lightroom. I'm wondering if there are some tips or tricks, or maybe hidden options on Facebook that makes the images served to the viewers higher ...
3
votes
3answers
6k views

Why does simply saving a JPEG at 100% quality in Photoshop increase filesize?

If I take a picture taken with my EOS 60D, put it into Photoshop, edit it as I wish and save it as JPEG with maximum quality, the file goes from 5 to 12 mb in size. Obviously if I didn't increase the ...
3
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4answers
15k views

Does converting RAW files to TIFF lose image quality?

Before I found out about Camera Raw, I used to convert my photos from RAW to TIFF, using the XNVIEW convertor, downloaded from the Internet. My question is whether I lost image quality or anything ...
6
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4answers
5k views

Why does Darktable export enormous JPEGs?

I have a Nikon D3200 and just started shooting in Raw. Raw files are 18-24mb, and if I convert them to JPEG using Nikon's ViewNX 2, I get 8-12mb files at the top quality and resolution using sRGB; ...
3
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3answers
3k views

Does reducing Lightroom export file size reduce image quality?

Sometimes I reduced the file sizes of my jpeg images for faster uploading to the web. Does this reduce the image quality?