A 1×1 grey pixel in 125 bytes using arithmetic coding, still in the JPEG standard even if most decoders can’t decode it: ff d8 : SOI ff e0 ; APP0 00 10 4a 46 49 46 00 01 01 01 00 48 00 48 00 00 ff db ; DQT 00 43 00 03 02 … Read more
The .Net encoder built-in to the library (at least the default Windows library provided by Microsoft) is pretty bad: http://b9dev.blogspot.com/2013/06/nets-built-in-jpeg-encoder-convenient.html Partial Update I’m now using an approach outlined here, that uses ImageMagick for the resize then jpegoptim for the final compression, with far better results. I realize that’s a partial answer but I’ll expand on … Read more
section 11.3.4.2 of the PNG spec gives a list of pre-defined meta tags (keywords) http://www.w3.org/TR/PNG/#11textinfo you can add as many other meta tags/fields as you would like. as for how, programmatically, that depends on the language you’re using!
Image i = Image.FromFile(“image.jpg”); If you need more information, here is the link.
You can save an image as ‘png’ and use the python imaging library (PIL) to convert this file to ‘jpg’: import Image import matplotlib.pyplot as plt plt.plot(range(10)) plt.savefig(‘testplot.png’) Image.open(‘testplot.png’).save(‘testplot.jpg’,’JPEG’) The original: The JPEG image:
Use ImageMagick v7: magick input.webp output.jpg Or ImageMagick v6: convert input.webp output.jpg If you have lots to do, use mogrify instead. So, say you want to convert all the WEBP images in the current directory to JPEG: magick mogrify -format JPEG *.webp And if you want the converted files in a directory called OUTPUT, use: … Read more
Edit: Version 1.5.0 (July 2017) of the Extensions to the PNG 1.2 Specification has finally added an EXIF chunk. It remains to be seen if encoders-decoders begin to support it. Original: PNG does not embed EXIF info. It allows, however, to embed metadata “chunks” inside the image. Some of the standardized chunks correspond to a … Read more
See this solution. https://github.com/nbadal/android-gif-encoder It’s an Android version of this post. http://www.jappit.com/blog/2008/12/04/j2me-animated-gif-encoder/ To use this class, here is an example helper method to generate GIF byte array. Note here the getBitmapArray() function is a method to return all the Bitmap files in an image adapter at once. So the input is all the Bitmap files … Read more
The second argument of the function is the quality. It ranges from 0.0 to 1.0 canvas.toDataURL(type,quality); Here you have extended information And I don’t think it’s possible to know the quality of the image once is converted. As you can see on this feedle the only information you get when printing the value on the … Read more
Nowadays this is pretty simple. The basic idea is: SVG to canvas canvas to dataUrl trigger download from dataUrl it actually works outside of the Stack Overflow snippet var btn = document.querySelector(‘button’); var svg = document.querySelector(‘svg’); var canvas = document.querySelector(‘canvas’); function triggerDownload (imgURI) { var evt = new MouseEvent(‘click’, { view: window, bubbles: false, cancelable: … Read more