# How to change pixel size of a photo and export



## Yvon (Sep 12, 2020)

Hi, I’m new to Lightroom and I’m doing well but I’m not very technical, can anyone help me please?  I want to alter the pixel size of a photo, to specific dimensions and  export to photos on my Mac.  I’m unsure as to where I make the changes Or if it is possible.   There doesn’t seem to be anything about sizing in the cropping function and when I click on ’export’ and open up choose sizing, the settings box only gives an option for changing the long side of a photo and not the width.  Thanks


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## clee01l (Sep 12, 2020)

First, let me say that pixels have no dimensions in the RGB file.  The Pixel dimensions are hard wired into the video display and the printer used to create the target image. 

Now to your question about resizing. This translates the number of pixels on the x and y axis to new values. Generally you do not want to change the Aspect ratio because this distorts the image.

Your camera shoots images the are approximately 3:2 aspect ratio. Your iMac has a display that is fixed at 16:9 aspect ratio. 
To get the camera image to fit into the display size you either end up with black space on the sides or you need to crop in LR to the aspect ratio of the display. 

When you export, you will have an option to not resize and if you use that then the software that displays your exported image will have to manage the size it displays. If it has a "fit" option then it will translate the pixels of the image file to fit the pixel dimensions of the display. 
If when you export you want to resize the image from the original (cropped or uncropped) size. there is an image sizing section with a checkbox labeled "Resise to fit:"   The field that reads "Long Edge" is actually a dropDownList box with other options.   If you Choose "Width & Height" or "Dimensions",  you get the option to distort the current aspect ratio.   You probably don't want to do that.   If you choose one of the edges, the current aspect ratio will be used and the long edge will be translated to the chosen pixels and the short edge will be proportion accordingly to fit the current Aspect ratio.


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## Jim Wilde (Sep 12, 2020)

clee01l said:


> If you Choose "Width & Height" or "Dimensions",  you get the option to distort the current aspect ratio.   You probably don't want to do that.


The OP is using Lightroom Desktop, which only has a Long Edge option. And although Classic has a "Width & Height" option, it's  not possible to "distort the image" there either. If the Width & Height entered do not comply with the current aspect ratio of the image, Classic applies the entered value of the longest edge, and the other dimension will be reduced to match the actual aspect ratio.


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## clee01l (Sep 13, 2020)

Jim Wilde said:


> The OP is using Lightroom Desktop, which only has a Long Edge option. And although Classic has a "Width & Height" option, it's not possible to "distort the image" there either. If the Width & Height entered do not comply with the current aspect ratio of the image, Classic applies the entered value of the longest edge, and the other dimension will be reduced to match the actual aspect ratio.



Sorry, using Tapatalk to read posts and this info is not available on that app. 
Every this I said applies except for the difference in the Export dialog. 


Sent from my iPad using Tapatalk


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## Yvon (Nov 20, 2020)

Jim Wilde said:


> The OP is using Lightroom Desktop, which only has a Long Edge option. And although Classic has a "Width & Height" option, it's  not possible to "distort the image" there either. If the Width & Height entered do not comply with the current aspect ratio of the image, Classic applies the entered value of the longest edge, and the other dimension will be reduced to match the actual aspect ratio.


Hi Jim, thanks for your reply.  I seem to have lost or forgotten where the ‘long edge’ option is...I can’t find it in the export options and can’t see it anywhere else.   I saw it a few weeks ago but can’t find it at all now, can you advise please? Many thanks


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## Jim Wilde (Nov 20, 2020)

When you click of the Share Icon, third from the right at the top right, choose Custom Settings from the Export section. Then in the resulting Settings dialog, click the down arrow to the right of Dimensions and choose Custom from the options. Then the "Long Side" option will appear....


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## Yvon (Nov 20, 2020)

Jim Wilde said:


> When you click of the Share Icon, third from the right at the top right, choose Custom Settings from the Export section. Then in the resulting Settings dialog, click the down arrow to the right of Dimensions and choose Custom from the options. Then the "Long Side" option will appear....


.  There it is, how the heck did I miss that?! Thanks Jim


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