68

I want to convert a batch of images, nearly 100, from jpg to png format. How can I do this without renaming them, but instead actually converting the format?

4
  • Use the convert command. No, really. But you will want to rename them from something.jpg to something.png.
    – Jos
    Apr 29, 2014 at 10:59
  • 1
    @jos, From your comment I don't understand that what should I do!!
    – opu 웃
    Apr 29, 2014 at 11:03
  • I wasn't finished editing ;-) First, use the convert command on a single .jpg file and see if it works. Then, write a script that loops over the .jpg files and converts them to .png files.
    – Jos
    Apr 29, 2014 at 11:05
  • You not mentioned how can I use the convert command on a single .jpg file. And I don't know how to write a script that loops over the .jpg files.
    – opu 웃
    Apr 29, 2014 at 11:13

4 Answers 4

97

Try these commands,

mogrify -format png /path/*.jpg    

This will convert all the .jpg files into .png files and saves the converted files in the same directory.

mv /path/*.png ~/Desktop/pic

This will moves all the .png files(converted) to the pic directory which resides on the Desktop.

Disclaimer:

If you want to keep the orientation of your image you have to add -auto-orient to the command. You can find out why here. The mogrify command which keeps the orientation would look like this:

mogrify -auto-orient -format png /path/*.jpg    
10
  • Should I change the directory?
    – opu 웃
    Apr 29, 2014 at 11:14
  • 1
    /path/*.jpg represents the directory where the .jpg files are stored. Apr 29, 2014 at 11:30
  • I also tried this command after changing the directory: mogrify -format png .jpg This also works nicely.
    – opu 웃
    Apr 29, 2014 at 13:38
  • The answer below is better, as it takes into account the limits placed on ARGV. May 16, 2017 at 2:57
  • 1
    is mogrify command lossless?
    – Mona Jalal
    Nov 13, 2019 at 16:39
61

Using ImageMagick.

First install imagemagick:

sudo apt-get install imagemagick

Try converting just one image at first:

convert image.jpg image.png

Now convert all:

mogrify -format png *.jpg

EDIT

You also need to split it into chunks that will fit to avoid hitting the limit of how much you can put on a command line. This should work better:

find -name '*.jpg' -print0 | xargs -0 -r mogrify -format png

The -print0 and -0 are used to handle spaces in filenames and the -r means don't run mogrify if there's nothing to do.

Source: https://stackoverflow.com/questions/1010261/running-a-batch-with-imagemagick

EDIT 2 Switched png and jpg as per @Glutanimate's comment.

EDIT 3 Changed png to jpg in last suggestion.

8
  • One image converted successfully. But when I used command to convert all its showing mogrify.im6: unable to open image ``*.png': No such file or directory @ error/blob.c/OpenBlob/2638.``mogrify.im6: unable to open file ``*.png' @ error/png.c/ReadPNGImage/3667.
    – opu 웃
    Apr 29, 2014 at 11:32
  • You will have to cd to that directory first. If they are in the desktop, run cd ~/Desktop first then try converting again.
    – Parto
    Apr 29, 2014 at 11:34
  • I changed the directory
    – opu 웃
    Apr 29, 2014 at 11:35
  • @Parto I think it should be mogrify -format png *.jpg. The OP is asking about converting jpg → png. Apr 29, 2014 at 13:01
  • did not work for me with 14.04 @Parto
    – talha06
    Jun 18, 2016 at 14:48
3

Firstly, convert works. You don't need to test it. Secondly, a bash oneliner suits the need:

$ for file in Ground*jpg; do { \
  echo "Converting $file to `echo $file|cut -d. -f1`.png" ;\
  convert $file `echo $file|cut -d. -f1`.png ; } done

Rockin' it auldskewl ;)

Cheers

0

I know it's been a long time since this question was put but there is one brilliant piece of software that has not been mentioned that I have used a lot.

http://photobatch.wikidot.com/ also known as Phatch. It literally converts anything from anything to anything else in image terms. It had not been updated for a while but now claims to be released for ubuntu 17.10. Give it a try. I'm confident you'll be very happy with it.

1
  • 2
    Tried to get this software, the "download" link to the deb file is missing from the above link, and the Ubuntu "store" version gave me this error: Detailed errors from the package manager follow: apt transaction returned result exit-failed Ubuntu v 18.10 maybe? Anyway - my experience. Jul 17, 2018 at 2:54

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