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Questions tagged [image-compression]

The objective of image compression is to reduce irrelevance and redundancy of the image data in order to be able to store or transmit data in an efficient form. Image compression may be lossy or lossless.

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Optimize uploaded images with php (jpeg)

When running Page Speed in Google Chrome it suggests to optimize/compress the images. These images are mostly uploaded by users, so I would need to optimize them during uploading. What I find about optimizing jpeg images with php is something like…
Juvlius
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Using SVD to compress an image in MATLAB

I am brand new to MATLAB but am trying to do some image compression code for grayscale images. Questions How can I use SVD to trim off low-valued eigenvalues to reconstruct a compressed image? Work/Attempts so far My code so far…
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why DCT transform is preferred over other transforms in video/image compression

I went through how DCT (discrete cosine transform) is used in image and video compression standards. But why DCT only is preferred over other transforms like dft or dst?
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How to implement image compression on-the-fly with Nginx?

Problem to solve: I'm on a CentOS platform. I would like to have static image assets (jpg/gif/png) compressed for optimized web serving (without resizing), while keeping the originals. For example, Request sent to http://server-A/images/image.jpg…
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PHP Imagick JPEG Optimization

I'm using PHP Imagick to resize images at runtime. The site has an image upload feature and we can't trust the user to use web-friendly JPEGs, as during the mass-import there are many 3 to 5MB images, and even a few as large as 13MB. Each image…
MaKR
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Besides standard/progressive, the 3rd kind of JPEG compression: load by channel?

this question might be an "Open Question" and many of you might be eager to close it, but please don't. Let me explain. As we all know, JPEG has two kinds of compression (at least in Photoshop save dialog) optimized, where image was loaded kinda…
est
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Flutter Web: How Do You Compress an Image/File?

Flutter Web is currently in beta, so there's a lack of available info/resources on how to do this. I could not find any flutter packages compatible with web to do this. Any tips? Here's my code: uploadImage() async { File file; FileReader fileReader…
Kai Selekwa
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BPG image format on Android

I think somebody heard something about a new format of images - BPG. Can i handle it on Android, any ideas? PS: BPG is really interesting format, for example, just checkout difference with jpeg UPDATE another examples of difference here and here
user4300069
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OSX: Execute same command on all files within a folder

i am using a command-line tool called TMX (https://github.com/tonybeltramelli/TMXResolutionTool) I want to execute this command on every .png file in a certain folder. How can i do that? This is how it is used: TMXResolutionTool
Eyeball
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Compressing png images using PHP

I'm looking for a PNG compression algorithm/library in PHP that is similar to: https://tinypng.com/ It's compression is by the best Any ideas out there on ones to check out? Google didn't net too many good results.
onassar
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How to reduce the palette of PNG image in Python/Pillow to the colors being really used?

After processing a previously optimized indexed color PNG image with transparency (see here for some background, since this question refers to the same image file), using the following code, the PLTE chunk seems to be expanded with more colors than…
Victor Domingos
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Unable to create image from compressed texture data (S3TC)

I've been trying to load compressed images with S3TC (BC/DXT) compression in Vulkan, but so far I haven't had much luck. Here is what the Vulkan specification says about compressed…
Silverlan
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Android picture compression without loading fully into memory

Is there any way to compress image without fully loading it into memory? As I understand BitmapFactory.decodeStream and similar methods load everything in memory and only after loading entire picture it can be compressed via Bitmap.compress My task…
Art
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How can I generalize the quantization matrix in JPEG compression?

I'm working on JPEG image compression where I investigated the use of the quantization matrix which is usually given in literature, but I want to write program so that when I vary the matrix, the number of bits per pixel to represent should also…
P.Bisoyi
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How to convert my photos to webp format of Google in windows 8.1?

I want to convert my photos from jpg, gif, and png to WebP format. When I'm trying to use CMD for using cwebp command, I got this error message : 'cwebp' is not recognized as an internal or external command, operable program or batch file. What…
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