Resizing Images on Export from Lightroom: I’ve tried to create jpg files of a specific size when exporting from Lightroom but the jpg files that get created are much smaller than I...

BushDog Loc: San Antonio, TX

I’ve tried to create jpg files of a specific size when exporting from Lightroom but the jpg files that get created are much smaller than I specified in the criteria. Does anyone have ideas on what I might be doing wrong?

Back story: I’m trying to create 1.5 MB files so that five or six files will not exceed 10MB. I designated criteria of 1.5MB and 300 dpi. The files that Lightroom created are in the 500KM to 700KB range.

robertjerl Loc: Corona, California

BushDog wrote:

I’ve tried to create jpg files of a specific size when exporting from Lightroom but the jpg files that get created are much smaller than I specified in the criteria. Does anyone have ideas on what I might be doing wrong?

Back story: I’m trying to create 1.5 MB files so that five or six files will not exceed 10MB. I designated criteria of 1.5MB and 300 dpi. The files that Lightroom created are in the 500KM to 700KB range.

LR used to allow you to set the size for the long side of an exported image - that option disappeared from Lightroom Classic CC a few upgrades ago.

rwilson1942 Loc: Houston, TX

robertjerl wrote:

LR used to allow you to set the size for the long side of an exported image - that option disappeared from Lightroom Classic CC a few upgrades ago.

That option is still available in LR Classic CC, latest version.
I use it all of the time.

robertjerl Loc: Corona, California

rwilson1942 wrote:

That option is still available in LR Classic CC, latest version.
I use it all of the time.

Then I need to check my settings, because yesterday I couldn't find it when exporting something - maybe a "helpful" feature in an update reset everything. I have had Windows updates reset everything to Microsoft Defaults and then had to go through everything and set them to my preferences.

rwilson1942 Loc: Houston, TX

What JPEG quality setting are you using?
I don't think LR will enlarge an image to match the 'limit file size to' setting.

robertjerl Loc: Corona, California

rwilson1942 wrote:

What JPEG quality setting are you using?
I don't think LR will enlarge an image to match the 'limit file size to' setting.

I usually use the highest setting to preserve details.

rwilson1942 Loc: Houston, TX

robertjerl wrote:

Then I need to check my settings, because yesterday I couldn't find it when exporting something - maybe a "helpful" feature in an update reset everything. I have had Windows updates reset everything to Microsoft Defaults and then had to go through everything and set them to my preferences.

Yep, you never what they might do to you to "improve" things.

Linary Loc: UK

BushDog wrote:

I’ve tried to create jpg files of a specific size when exporting from Lightroom but the jpg files that get created are much smaller than I specified in the criteria. Does anyone have ideas on what I might be doing wrong?

Back story: I’m trying to create 1.5 MB files so that five or six files will not exceed 10MB. I designated criteria of 1.5MB and 300 dpi. The files that Lightroom created are in the 500KM to 700KB range.

The problem is that LR does not export to a "size on disc" which is (I think) the size you are looking for.
The export dialogue mentions

RESIZE TO FIT - and various ways of looking at the size, all of which are to do with the image size or dimensions in pixels, not the size on disc.

The size on disc is controlled by the quality setting (jpegs) and no two jpeg images will be the same. The simplest jpg will be an image of a black cat in a coal cellar and will yield a different number of bytes on disc to that of an image of a multicolored cat in a flower greenhouse.

In LR, uncheck the box "Resize to fit", and export the same jpeg two or three times at different quality settings. (the dpi - which is actually ppi - does not make a difference to the file or image size).

Linary Loc: UK

robertjerl wrote:

Then I need to check my settings, because yesterday I couldn't find it when exporting something - maybe a "helpful" feature in an update reset everything. I have had Windows updates reset everything to Microsoft Defaults and then had to go through everything and set them to my preferences.

One of the annoying things about LR export dialogue is that if the slider is used to scroll down the dialogue the Image Sizing panel sometimes is skipped. this does not happen when the little arrows above and below the slider are used.

How to reset LR Preferences:
https://helpx.adobe.com/lightroom/help/setting-preferences-lightroom.html

BushDog Loc: San Antonio, TX

Here is some more insight into my original post.
I started with raw files using 24MP and 42MP cameras.

I just now exported (from Lightroom) some new jpg files for a different project. This time I used 1.5 MB and 600 dpi (instead of 300 dpi). The resulting files were significantly larger ... some actually larger than the 1.5 MB criteria.

BushDog Loc: San Antonio, TX

Thank you, Linary. I did mistake megapixels for megabytes on the resize option.

Linary wrote:

The problem is that LR does not export to a "... (show quote)

robertjerl Loc: Corona, California

Linary wrote:

One of the annoying things about LR export dialogue is that if the slider is used to scroll down the dialogue the Image Sizing panel sometimes is skipped. this does not happen when the little arrows above and below the slider are used.

How to reset LR Preferences:
https://helpx.adobe.com/lightroom/help/setting-preferences-lightroom.html

Been there, done that, it can really skip a bunch if you drag the slider.

BudsOwl Loc: Upstate NY and New England

BushDog wrote:

I’ve tried to create jpg files of a specific size when exporting from Lightroom but the jpg files that get created are much smaller than I specified in the criteria. Does anyone have ideas on what I might be doing wrong?

Back story: I’m trying to create 1.5 MB files so that five or six files will not exceed 10MB. I designated criteria of 1.5MB and 300 dpi. The files that Lightroom created are in the 500KM to 700KB range.

I just ran an experiment. I took a photo with 5184 x 3456 pixels (21.6 x 14.4 inches) and exported it with a size limit of 1.5 mb. The final size was 1.39 mb. Were your jpgs significantly smaller? If so, did you set a maximum length in the setup. Aside from the max limit of 1.5 mb everything else should have been blank (although you could set the ppi since it would not have impacted your result).
Bud

R.G. Loc: Scotland

The problem may be due to the fact that file size isn't continuously variable - in other words the file size is adjustable only in jumps. It's possible that with the size limit that you're using, and with the type of image that you're exporting, the next jump up from 700KB would be bigger than 1.5MB. Try setting the limit to 1.8MB (or higher if necessary).

Other than that, check that the Quality slider in the File Settings section is at maximum and check that you haven't inadvertently left the Image Sizing section active by leaving the "Resize to Fit" box checked.

abc1234 Loc: Elk Grove Village, Illinois

I have other explanations. First, cropping reduces the size of the export. Second, jpg compression works by, in part, by mapping where a specific color is. If you have a lot of the same red, the file will be smaller than if you have a lot of shades of red.

However, as a practical matter, you do not need to resize the jpg. All you have to do is crop to the desired aspect ratio. The printer will resize to the output size. This way, you can avoid having unnecessarily large files. I do not know why the OP wants that size but I think he may want to email the pictures. When I want to email pictures, I might limit the size to 1 or 2 M but if I do not or have too many pictures, I simply use dropbox.