These instructions help you to resize your image after you have edited and cropped your image to suit your needs. Your resized images must be no larger than 1440 pixels wide by 1080 pixels high including any borders. Projected digital images must be saved in JPEG file format. Images are projected in sRGB colour space.
This process is suitable for Lightroom.
In the Library view, click on "Export..." In the "File Settings" section:
Set "Image Format" to "JPEG".
Set "Quality" to 100. (If the image is being resized down to the target dimensions this is unlikely to be a problem in terms of file size).
Set "Color Space" to "sRGB".
Ensure"Limit File Size To:" is un-checked.
In the Image Sizing section:
Ensure "Resize to Fit" is checked.
Choose the "Width & Height" option.
Set the "W:" and "H:" values to e.g. 1440 and 1080, and the units to "pixels".
Set "Resolution" to 300 pixels per inch.
Ensure "Don't Enlarge" is checked.
You may then want to save those settings as a Preset (use the "Add" button below the Preset pane on the left). Note that setting both the width and the height is correct, irrespective of the image's aspect ratio. Lightroom will adjust both the height and the width together (maintaining the aspect ratio) ensuring that neither is too big.