Content Aware Resizing in Gimp

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In a previous post, I looked at content aware resizing in Photoshop CS4 which is the same as in CS5. I also mentioned the online application called Rsizr. Today I’m going to show you a plug-in for Gimp that does pretty much the same thing.

The tool is called Liquid Rescale which you can download from here. Close Gimp, install the application and then reopen Gimp and you will see the application on the Layer menu.

gimp_content_aware_resizing_liquid_rescale_1.jpg

This plug-in is an alternative to the crop tool. You use it to reduce an image’s size but, where the crop tool removes the data from one or more sides of an image, content aware resizing removes it from the middle of the image. This gives you basically the same looking image but smaller in one dimension. You might use this, for example, to remove some empty area from the middle of an image where the more interesting parts of the image are to either side of it.

The same tool can scale an image up to make it larger in one direction – and this time it will create extra data in the image to fill the space. You might use this, for example, where you have a rectangular image that you want to make into a square image without losing any detail.

To see how this can be done, I’ll take this beach image and size it down from 3571 pixels wide to 3000.

gimp_content_aware_resizing_liquid_rescale_2.jpg

Open the image in Gimp and choose Layer > Liquid rescale. When the dialog appears, click the Output tab and set Output Target to a New Image. Enable the Resize image canvas checkbox and click Ok.

gimp_content_aware_resizing_liquid_rescale_3.jpg

Set the new image width – I set this to 3000 but made sure that the link icon was disabled as I don’t want the height altered. Click Interactive and wait as the image is resized.

gimp_content_aware_resizing_liquid_rescale_4.jpg

The program resizes the image by removing unimportant details from it and keeping what it understands to be the important bits. This is the result:

gimp_content_aware_resizing_liquid_rescale_5.jpg

If you find that some elements in the image are squeezed or damaged by the process, you can create a mask to prevent this from happening.

To do this, click the original image again and choose Layer > Liquid rescale and set up the Output tab options.

Click Feature Masks and, to create a protective mask, click the Feature Preservation Mask option and click New. The paint color will be set to green so select a brush, enlarge it to an appropriate size and paint over anything on the image that you do not want to change as the image is resized.

gimp_content_aware_resizing_liquid_rescale_6.jpg

In my case, that is the swimmer at the front of the image and the lifeguard and boards at the back. I’ve added some other bits I don’t want skewed out of alignment like the vertical poles too. Anything else can be adjusted except these elements. When you’re done, click Ok.

Type the size for the new image and click Interactive and wait as the image is resized. Here I chose for the image to be reduced from 3571 to 2500 pixels wide, and the surfer, boards and flags have all reduced well. The protected areas have not been touched.

gimp_content_aware_resizing_liquid_rescale_7.jpg

The plug-in also has a tool that you can use to remove elements from the photo. In my image let’s take out the large pole in the foreground. In this case you use a Feature Discard Mask – and paint in red over the area that you want removed from the image. Adjust the strength to the highest value, set the width value by clicking Auto size: Width so that the image is scaled to the appropriate width for the item you are removing and click Interactive.

gimp_content_aware_resizing_liquid_rescale_8.jpg

In this case, the flag has gone but we’ve got a bit of a repair job to do with the rest of the image to fix it up. It would require some work with the clone tool to fix up the image but Liquid rescale has got us some part of the way towards where we are headed.

gimp_content_aware_resizing_liquid_rescale_9.jpg

You can also use the plug-in to enlarge an image. In this case, we’ve enlarged the image to create a square image.

gimp_content_aware_resizing_liquid_rescale_10.jpg

The rescaling process isn’t perfect but generally you’ll get a good enough result that with a small amount of cloning afterwards using the clone tool you’ll be able to produce a realistic result.

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Helen Bradley is a Lifestyle journalist who divides her time between the real and digital worlds, picking the best from both. She writes and produces video instruction for Photoshop and digital photography for magazines and online providers world wide. She has also written four books on photo crafts and blogs at Projectwoman.com.

  • cathode

    Lets put copyright logos, names and website URLs on simple screenshots now, sure.

  • @cathode If you can find a way to stop folks from taking all this content and republishing this on their own blogs and passing it off as if they did it all themselves, I’ll happily save myself the effort of badging it as being my work not theirs for every screenshot I take. Sadly it is the best way I know of ensuring that people know who wrote this stuff when they see it all over the web. Doing this saves me getting angry every time someone uses my work without permission. Too often, often within hours of a post appearing here it will be on multiple other sites posing as original content without even a reference to DPS.
    Helen

  • Shawn M

    Lawyered!

  • Bekah

    Thanks for another Gimp tutorial! Really appreciate them.
    Also–I didn’t even notice the logo until I read the comments and scrolled back up. Definitely not an obnoxious and distracting

  • Liquid Rescale is really a pretty amazing plugin. I’ve used it in the past to get a few extra pixels on one side of a photo when I failed to leave enough room to get the crop that I want.

    And yeah, it’s not difficult to find ripoff sites that take the entire content of a DPS article and post it as their own. Content Scrapers, I believe is what they’re called.

  • That’s interesting.

    Another way to do it is to download the Resynthesizer plugin. The install is kind of a pain, but there are fewer steps when fixing a picture.

  • Thanks for the tutorial. I’ll definitely add this to the GIMP toolbox.

  • I’ll absolutely be checking this out, thanks for sharing.

    Keep the gimp tutorials coming.

    …and the watermarks are not distracting.

  • sillyxone

    thanks for the tutorial, I played with it a few years back but it wasn’t stable enough so I didn’t know that it’s getting so good now.

    BTW, the tutorial videos on their site are also very good, especially about how to “debug” in case things go wrong.

Some Older Comments

  • sillyxone November 17, 2011 08:31 am

    thanks for the tutorial, I played with it a few years back but it wasn't stable enough so I didn't know that it's getting so good now.

    BTW, the tutorial videos on their site are also very good, especially about how to "debug" in case things go wrong.

  • DM|ZE November 16, 2011 03:26 am

    I'll absolutely be checking this out, thanks for sharing.

    Keep the gimp tutorials coming.

    ...and the watermarks are not distracting.

  • Rick November 15, 2011 04:45 am

    Thanks for the tutorial. I'll definitely add this to the GIMP toolbox.

  • sixmats November 14, 2011 08:03 pm

    That's interesting.

    Another way to do it is to download the Resynthesizer plugin. The install is kind of a pain, but there are fewer steps when fixing a picture.

  • Rick November 14, 2011 01:36 pm

    Liquid Rescale is really a pretty amazing plugin. I've used it in the past to get a few extra pixels on one side of a photo when I failed to leave enough room to get the crop that I want.

    And yeah, it's not difficult to find ripoff sites that take the entire content of a DPS article and post it as their own. Content Scrapers, I believe is what they're called.

  • Bekah November 14, 2011 01:07 pm

    Thanks for another Gimp tutorial! Really appreciate them.
    Also--I didn't even notice the logo until I read the comments and scrolled back up. Definitely not an obnoxious and distracting

  • Shawn M November 14, 2011 09:33 am

    Lawyered!

  • Helen Bradley November 14, 2011 07:57 am

    @cathode If you can find a way to stop folks from taking all this content and republishing this on their own blogs and passing it off as if they did it all themselves, I'll happily save myself the effort of badging it as being my work not theirs for every screenshot I take. Sadly it is the best way I know of ensuring that people know who wrote this stuff when they see it all over the web. Doing this saves me getting angry every time someone uses my work without permission. Too often, often within hours of a post appearing here it will be on multiple other sites posing as original content without even a reference to DPS.
    Helen

  • cathode November 14, 2011 03:58 am

    Lets put copyright logos, names and website URLs on simple screenshots now, sure.

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