How to resize an image using ImageMagick

Question

From How to easily resize images via command-line? I know I can use this command to resize an image in bash:

convert -resize 1024X768  source.png dest.jpg

But I'm stuck at only providing the width and keeping the aspect ratio.

man convert does not provide any help for -resize flag.

I want something like convert -resize 1024 -keep-ratio source.png dest.png

What would be the command?

https://askubuntu.com/a/25134 - after following your link. Seems ! signifies don't keep aspect ratio — Hannu, Dec 26 '22 at 11:18
@Hannu, I want to keep the aspect ratio. None of the commands in the answer link you mentioned do that. I need to keep aspect ratio, and I need to only provide the width. — Saeed Neamati, Dec 26 '22 at 11:28
Yes!? So, as I understand the examples; do NOT include a !, — Hannu, Dec 26 '22 at 11:30
@Hannu, then what is the command? I'm confused. I have not included ! in my question. — Saeed Neamati, Dec 26 '22 at 11:32

codlord · Accepted Answer · 2022-12-29T14:03:10.173

2

convert -resize by default does keep the aspect ratio (unless ! is specified). So to resize based on width alone you would just need to do: convert -resize 1024 source.png dest.png

To convert based on the height alone for example: convert -resize x768 source.png dest.png

-resize takes the Geometry parameter. Take a look at the docs I linked as well as resize examples.

edited Dec 29 '22 at 14:03

answered Dec 26 '22 at 11:34

codlord

2,506

that worked great. Now I'm in a situation that I need to resize based only on height. If I provide a single value, it takes it as the width parameter. What syntax should I use? – Saeed Neamati Dec 29 '22 at 04:19
@SaeedNeamati I updated my answer above. – codlord Dec 29 '22 at 14:04
thank you so much. – Saeed Neamati Dec 30 '22 at 13:22

How to resize an image using ImageMagick

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