Howto: Linux convert an image between different formats from command prompt

by on May 2, 2007 · 5 comments· LAST UPDATED May 2, 2007

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Q. How do I convert images from a shell prompt? For example convert an image in the JPEG format to PNG or vise versa?

A. You need to use the convert command which is a member of the ImageMagick suite of tools. Use it to convert between image formats as well as
=> Resize an image
=> Blur an image
=> Crop an image
=> Despeckle an image
=> Dither an image
=> Draw on an image
=> Flip an image
=> Join an image
=> Re-sample, and much more.

Task: Convert an image in the JPEG format to PNG

Type the command as follows:
$ convert input.jpg output.png

Task: Resize the image

Resize and convert an image in the JPEG format to PNG
$ convert -resize 50% input.jpg output.png

You can also create a complex effect such as:
$ convert -size 360x85 xc:transparent -font Bookman-DemiItalic -pointsize 72 -draw "text 25,60 'nixCraft'" -channel RGBA -gaussian 0x6 -fill YellowGreen -stroke RosyBrown -draw "text 20,55 'nixCraft'" nixCraft.png

Output:

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{ 4 comments… read them below or add one }

1 Dhaval April 18, 2008 at 12:12 pm

This website is the best …website for linux users.

Thanks to Nixcraft.

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2 pear December 14, 2009 at 5:30 pm

Hi ,

I have converted *.bmp to *.ps, but the *.ps image appears to be small and displayed at the end of the page. How to delete the empty spaces and make it fit to the page with a full resolution.

I had a similar problem with ps2pdf but i used ps2pdf -dEPSCrop *.ps , i got good result

Similarly how to do with bmp to ps conversion? or is there any way to convert bmp to pdf directly with full size fit?

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3 Dhavakumar February 1, 2010 at 6:36 pm

How to convert dot format to jpeg format

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4 elwoode February 28, 2013 at 9:47 am

how do you convert all the files in the folder from .jpg to .png BUT keep the same names apart from the different exstension.
I tried
convert *.jpg *.png
but of course I get a lot of png files with no names just *-0.png etc

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