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I have a batch of PNG files that I need to convert to JPEG. I'm looking for a free trustworthy utility that will give me the most optimal possible JPEGs.
I've found some paid utilities and i HAVE Photoshop, but I want something dedicated that is made for the task and I dont want to accidentally download spy ware.
I'm really surprised not to find this question already on StackOverflow, but please point me in the direction of any similar questions if they exist.
One word: ImageMagick.
Not sure about if it generates the absolute smallest JPEGs you can get, but it's certainly good and would be my first choice.
IrfanView is another option. It has a "Batch Convert/Rename" feature, but it's a Windows-only GUI app.
Imagemagick (http://www.imagemagick.org/script/index.php) can do batch conversion of images.
mogrify -format jpg *.png <= Converts all png files to jpg
The ImageMagick convert utility should do everything you require. There are a number of options which you can use to control the JPEG output quality.
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Apple has introduced a new image format in iOS 11 called HEIF (.heic file extension). I know you can export images as JPG from iOS devices, but I want to upload the HEIC-files to my server and convert them there to JPEG files that can be shown on all other devices.
Can anyone recommend a good and efficient way to achieve this?
ANSWER:
Since this question has been closed, I will edit in my answer here for the rest of you. We now use this library for converting HEIC to JPEG: https://github.com/monostream/tifig
Also ImageMagick now support converting HEIC to JPEG thanks to a fork from #toshic
Thank you to #monostream and #toshic for your great contributions!
EDIT1: Edited the wording of the question to be more specific and meet SO guidelines
EDIT2: Added answer since this topic is now closed :/
It's complicated because iOS 11 is actually storing tiles of HEVC encoded images in a HEIF container, but there's a demo using the nokia lib to extract them all, ffmpeg to decode them and then stitching them into a single jpeg with imagemagick in the heiftest repo linked from corrupted HEIC tile when converting to JPEG
We also have a working one you can use by cloning https://github.com/pushd/heif and then:
cmake CMakeLists.txt && make && Bins/heiftojpeg test_001.heic test_001.jpg
There is no such library available right now for image conversion on a server for HEIF to JPEG, ImageMagick doesn't have support for that till now.
The only way you can do this by exporting your images from your device, that should produce a JPEG image.
Nokia has a HEIF reader javascript implementation which you can have a look at: Nokiatech heif
Alternate: You can try this website if this works.
Feature Request for ImageMagick
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Sorry if this has been addressed before, I searched it up and I couldn't seem to find a question like this. I am making a social media app, and I want to preserve the quality of the images as much as possible. To make a data representation of the image I am using "UIImageJPEGRepresentation" and I would like to know what an optimal setting for the compression quality is.
One big consequence of setting the quality below 1 is that the image uploads to my server in much less time. I have experimented with the compression and to me I can't really tell the difference between 0.6 and 1 unless I zoom in on a computer, but I just wanted to know if there was a number or range that would produce favorable results.
One of the interesting and evolving format is Webp format that Google has introduced. This article suggests that Facebook is also trying to use this format. To answer the exact question as to how much to compress please note the following:
-Format of the image(I assume yours is JPEG)
-Compression technique(Lossy or Lossless)
-Target devices(I assume yours is mobile)
Considering above parameters(and more) and looking at the dimensions of all social networking sites I suggest you to get the compression level high enough such that you can see a difference in the image quality on the computer, that way you would have found an optimal level, remember lower the better till it degrades. Additionally you can find the information at this.
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I have an existing iTunesArtwork image
To modify the image I've converted it to png image
As I read that the iTunes artwork is nothing
but a png image without png extension
so I added a png extension and it became png image then I modified the image
then I removed the png extension and its not working as it supposed to be.
Any help is appreciated !
Thanks in advance !
The above steps are correct for window environment but in mac you have to follow the below steps/
Right click on the image -> Choose GetInfo -> Choose Name & extension
-> remove the extension.png -> close the GetInfo Box -> Give yes when prompted to save.
This is the way to remove or change extension in Mac
Hope this helps
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I am trying to format my book for a Kindle 3. I'm writing the book using LaTeX. I am ok with transferring the file in PDF format but I need it formatted to be small.
I have tried:
\documentclass[12pt,b7paper]{book}
\usepackage[top=0.5cm, bottom=0.5cm, left=0.5cm, right=0.5cm]{geometry}
But this is too small. I have also tried something like:
\usepackage[paperwidth=9cm, paperheight=12cm, top=1cm, left=1cm, right=1cm, bottom=1.5cm, includefoot]{geometry}
But that doesn't work well either. Has anyone found a good way to format a LaTeX PDF for the Kindle? (Not the big DX version.)
This works well. I found it important to remove paper size from the dvips command. Forgetting to adjust that setting through me off for a while.
\documentclass[12pt]{book}
\usepackage[paperwidth=9cm, paperheight=12cm, top=0.5cm, bottom=0.5cm, left=0.0cm, right=0.5cm]{geometry}
\special{papersize=9cm,12cm}
Why don't you convert the LaTeX to HTML and create a Mobipocket document from that? That way, the Kindle will be able to reflow the document, which it cannot do if you load it in PDF form.
This may be much more than you need, but it's worth pointing out that there's a much more comprehensive answer over on tex.stackexchange
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I'm trying to find a real time image processing tool that can do image resizing, image/text overlaying and format converting. I found some related posts but they don't quite answer my question.
Prioritized criteria for the tool:
The processing time needs to be less than 100 ms.
The size of output image needs to be small. It needs to convert 1 to 2 megabytes of jpeg image to around 75k.
The quality needs to be good. This is subjective. We know jpeg image conversion loses quality. I hope to find a tool that has better conversion algorithm such that the output is close to the original image.
It can be implemented in java or php.
One commonly used tool is GD library. GD library meets criteria 1 and 2. But the image quality is usually not great, which is the reason I'm still looking.
I tried ImageMagick through command line. The quality is better but the size of output image is also larger. I believe it's also slower than GD.
I wonder what real time image processing tool you'll recommend. If it's GD or ImageMagick, are there tricks to improve the overall performance?
Thank you!
I'd highly recommend graphicsmagick (http://www.graphicsmagick.org/). It's a fork of imagemagick with more of a focus on performance.
There are also tricks to getting imageMagick/gm to produce smaller images - for example you can strip the colour profiles from the images you create, eg:
gm mogrify -resize 180x180 -quality 75 +profile "*" image.jpg