Export settings for exporting 24MP size photos with full resolution? Lost my original settings when old pc failed.

All your answers were helpful.  jpeg XL is not really needed, and may not be accepted by Flickr.  Your answers give what I need to be sure I am exporting full images.  Thank you.

If you’re doing it the way Anshul and Johan are saying (leave Resize to Fit unselected, which is how it looks in your last Export screen shot), all the pixels will be there in the exported image, meaning all the resolution of the current crop is there.

You can troubleshoot where the problem is by verifying the exported images before uploading. Immediately after exporting, outside of Lightroom Classic, inspect the width and height, in pixels, of the exported images on the desktop. In your second screen shot, the dimensions are not shown, so click that Properties button to see them. (Some desktop window views might let you display image dimensions if you customize the desktop view settings, but I’m not sure how it works on your computer because I’m on a Mac.)

You can also use other photo editors, such as Adobe Photoshop or Bridge, to verify the exported dimensions. 

For example, in the picture below, in Lightroom Classic, the Loupe Info Overlay that I set up says my panorama is 10091 x 3805 pixels, and I export that with no resizing. I select the exported image in Adobe Bridge and also in a folder window on the (macOS) computer desktop, and both of those verify for me that the exported image is in fact 10091 x 3805 pixels, so all of the pixels are there…none are missing. The exports have full resolution on my end.

If you verify that the exported images have full resolution before you upload, then if the images have reduced resolution at any point beyond your computer, like on a web site such as Flickr, then the problem is not on your computer but somewhere down the line, like maybe on the web site where it was uploaded. Or maybe it was altered by settings in the uploader.

I have not used Flickr much lately, so I don’t know if they do any downsampling or recompression…but many social media services are known to degrade images in those ways. The only thing I did find out was that JPEG XL is not listed on their help page of acceptable file formats (https://www.flickrhelp.com/hc/en-us/articles/4404079649300-Flickr-upload-requirements).

It would also be nice to verify the image dimensions on the Flickr side after uploading, to see what they store. But the only place I could find that is if you open an image in the Flickr image editor, and then in the Transform tools, look in the bottom left corner for the current crop dimensions.

A little background:  Several years back, when LRC was installed on my Windows pc, I followed the steps in Martin Evening's Adobe Lightroom manual and set up the settings for exporting files out of LRC. The settings worked for years, with no need for change.  I would export my 24MP images to "My Pictures" on my hard drive, and then drag and drop them into a Flickr uploader.  The images displayed well.  Clicking on an image in Flickr would enlarge the display, and a second click would enlarge it still further with good detail.  When my pc died, it was replaced with another Windows pc.  Since then, the photos no longer display in Flickr with the same enlargement capability - sometimes with no display enlargement capability at all.  I am wondering if I should change my LRC export settings.  Are my settings wrong in the export dialog or does the problem reside with Flickr?  I did see the JPeg EL option, so I tried it; the exported file would not display its thumbnail image in "My Pictures", and generates a "This is not a picture" message when I attempt to upload it to Flickr. There may be a connection to the use of HDR on the images that generate the error message.  I have two questions.  What JPeg export settings should I use on my export dialog to ensure the fullest display of images; and does Adobe LRC offer a fix for my JPeg EL difficulty (The Microsoft Store tried to sell me a download to fix it)?

At present, images exported are no longer shown at full resolution or size, after switching to a new pc?

What does this mean? How do you know they are not at full resolution? How do you know they are not at full size? What evidence do you use to come to these conclusions? What file format are you exporting to (JPG, TIF, DNG, other)?

In the export dialog, there is an option to resize the exported image. Do not use resize and you’ll get the original size. Please remember that you can only judge the size by looking at the number of pixels, not by looking at the file size of an exported jpeg.

If you say that Lightroom does not export correctly to jpegXL, then tell us what goes wrong. Only then we can tell you if there is a fix.