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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Does JPEG compression reduce actual image size?

In this article it says "Generally speaking, the algorithm behind this format makes some trade-offs to lower the image size." Just wanted to check that this is referring to image file size, ...
-2 votes
2 answers
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custom raw compression

I'm planning to acquire between 50k and 200k image per day with a 50MPixels (or 68MPixels or 130MPixels) sensor; I'll be acquiring the raw data (10 or 12 or 14 bits) from the sensor through SLVS-EC ...
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Image properties for social media?

My experience of social media is extremely limited, but I have occasionally been asked by a group to send them an image for use on their media. Sometimes as non-technical people only used to mobile ...
1 vote
2 answers
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Capture one to export a progressive jpeg?

As far as I can tell, Capture One doesn't have the option to export an image as a progressive jpeg. To get a progressive image, I've been compressing once on export, and compressing again on the ...
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2 answers
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Can jpg be converted to progressive jpg without quality loss?

My understanding of a progressive jpg is that it saves the color information of each pixel in a different order, to create the progressive loading effect. I.e. instead of RGB RGB RGB ..., it's saved ...
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2 votes
1 answer
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Lightroom: Viewed image gets compressed

When I was working on an image in Lightroom I recognized that the image is compressed (see image below) but I always record my images lossless compressed. Also the image seems to be fine when exported ...
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2 answers
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Why does GIMP increase the size of exported JPEG files?

I'm using GIMP to edit some vacation pictures (JPEG files) taken with a rather old digital camera. Lacking a professional background, I just went about by trial and error and ended up adjusting the ...
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1 vote
1 answer
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Lightroom performance: Differences with compressed / uncompressed RAW files?

Is there a performance difference in Lightroom when editing (lossless or with losses) compressed RAW files instead of uncompressed RAW files? Even when it might not be noticeable? I could imagine that ...
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1 answer
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Does a TIFF file using JPEG compression have the same 65535 x 65535 pixel limitation as a JPEG file?

TIFF allows for JPEG compression, among others. While it is not a well-explored option (most people just opt for lossless compression), I am looking to use it as a similar-size alternative to JPEG, ...
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JPG files - different brightness in viewers

I have a single JPG file. If I open it with IrfanView, it is darker than the same file opened in PhotoShop (or in Firefox). What can cause this? The correct version is the one from Photoshop (or ...
2 votes
1 answer
780 views

What are the benefits of LZW compression for TIFFs?

I have few photos - JPEGs from smartphone, RGB, 8 bit per channel. Nature, landscapes. I want to edit them. Before editing I will convert JPEGs to TIFFs. I will use TIFF, RGB, 8 bit per channel. ...
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Lossless compressing TIF file

I have TIF files that I would like to compress without losing any data, do you know the best tool for that? The data is very important. The data file looks like this: I have thousands of them. (It's ...
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1 answer
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Watermarking processing proof

There are watermarking technologies in videos that are resistant to transcoding and image resizing. There are no visible artefact, it's rather for content protection and tracing. Is there anything ...
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Do I lose information every time I add an adjustment layer to an 8bit image in Photoshop?

A friend told me that one of the disadvantages of working with 8bits images within Photoshop is that every time I add an adjustment layer I lose some data. Is that true? Is there a quantifiable ...
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1 vote
4 answers
481 views

Lossy archival compression for 16-bit TIF images

I sometimes use the Nik collection to process my photos, and because this runs on TIFF images, I end up with demosaiced files eating up more disk space than they're worth. I want to batch convert ...
2 votes
1 answer
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Does compressing with chroma-subsampling multiple times degrade image quality?

Suppose I am creating a large image files out of smaller ones. The original images (jpeg) already have chroma-subsampling of 4:2:0. If one were to put them together and save again as a jpeg, would ...
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2 answers
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Is editing metadata of a JPEG destructive to the image?

Is editing metadata of a JPEG destructive to the image? If I edit "File Info" > "Description" in Photoshop, then save.... am I causing the same image degradation as if I edited the image, then re save ...
2 votes
3 answers
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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: ...
1 vote
2 answers
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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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4 answers
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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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2 votes
2 answers
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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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2 answers
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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 ...
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1 answer
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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 ...
22 votes
2 answers
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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 ...
33 votes
4 answers
7k 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 ...
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3 votes
1 answer
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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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2 votes
1 answer
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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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9 votes
4 answers
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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, ...
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2 answers
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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 ...
1 vote
3 answers
1k 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 votes
5 answers
9k 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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3 answers
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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 ...
1 vote
1 answer
503 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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1 answer
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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 vote
1 answer
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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 votes
1 answer
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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 ...
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3 votes
3 answers
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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 vote
1 answer
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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 ...
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2 answers
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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 votes
1 answer
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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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2 answers
1k 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 ...
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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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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.
4 votes
6 answers
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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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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 ...
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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 ...
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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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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 votes
1 answer
570 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 ...
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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 ...