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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49
votes
7answers
197k views

What quality to choose when converting to JPG?

When you export a picture to JPG you can normally choose its quality in a 1-100 scale. I like to keep a good quality but it wouldn't make sense to keep a JPG that will be almost as big as the original ...
3
votes
3answers
8k 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
votes
5answers
840 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) ...
3
votes
3answers
405 views

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
2answers
81 views

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 ...
1
vote
2answers
89 views

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 ...
2
votes
1answer
101 views

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 ...
1
vote
2answers
453 views

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 ...
1
vote
1answer
335 views

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 ...
32
votes
6answers
40k views

How can I tell exactly what changed between two images?

For example, for a recent conversation about JPEG compression I wanted to compare pixel for pixel what changed between two JPEGs (one with compression level 100, and one with compression level 95). ...
1
vote
1answer
972 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 ...
0
votes
1answer
209 views

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, ...
1
vote
0answers
84 views

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
1answer
504 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. ...
-1
votes
2answers
238 views

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 ...
25
votes
12answers
42k 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 ...
3
votes
1answer
180 views

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 ...
0
votes
2answers
120 views

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 ...
1
vote
4answers
359 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
1answer
75 views

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 ...
7
votes
10answers
182k views

How to reduce the file size of my photos (to under 15 MB)?

I don't have a "Pro" account on Flickr, just the free one, so my photo uploads are capped to 15 megabytes/file. After post-processing, my photos end up being too large to be uploaded to Flickr. I do ...
2
votes
2answers
808 views

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 ...
58
votes
1answer
19k views

Are "Windows Photo Viewer" rotations lossless?

Can I rotate lossily compressed photos that I view in Windows Photo Viewer without worrying about losing even more information to compression?
2
votes
3answers
2k 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: ...
6
votes
2answers
4k 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 ...
3
votes
6answers
1k 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 ...
1
vote
2answers
302 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 ...
4
votes
3answers
6k 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 ...
4
votes
5answers
2k views

How can I resize more than 2GB of travel photography with no quality compromise?

I have more then two gigabytes of travel photography. Each image takes up than 4 to 5 megabytes. I have to send them to some one. How can I resize all images while retaining high image quality?
1
vote
4answers
4k 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 ...
8
votes
4answers
22k 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, ...
1
vote
2answers
172 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 ...
2
votes
2answers
558 views

Good compromise on quality/compression for hi-rez photographs?

My Nikon D90 dumps out photographs that are 4288 x 2848 @ 300 DPI. They're about ~3 MB in size. I'm an amateur in every sense of the word. I don't know what 75% of the camera settings do. I'm ...
3
votes
2answers
869 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 ...
22
votes
2answers
6k 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 ...
-1
votes
2answers
490 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 ...
-1
votes
1answer
416 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 ...
33
votes
4answers
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 ...
8
votes
3answers
4k views

Does JPEG-to-JPEG export Lightroom reapply compression?

I want to crop a JPEG file in Lightroom and export that cropped file to another JPEG so that I can e-mail it. The exported JPEG should have the same quality as the original. I don't have the RAW file ...
3
votes
1answer
430 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 ...
2
votes
1answer
103 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 ...
3
votes
4answers
2k 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
votes
2answers
3k 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 ...
1
vote
3answers
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....
23
votes
3answers
34k views

Which TIFF image compression is better, LZW or ZIP?

Which image compression is better, LZW or ZIP? I am using Lightroom to export images.
3
votes
4answers
19k 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 ...
4
votes
5answers
7k 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 ...
10
votes
2answers
9k 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 ...
1
vote
1answer
454 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 ...
1
vote
1answer
2k 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 ...