Is there a way in LR to find photos based on file size?
For a project I had some time ago, I made a useful list of images by file size not in Lightroom, but in the Finder. For some purposes this might be a cumbersome approach, but it worked for me.
Start by selecting in the Finder the folder the contents of which you want to sort by file size; then in the search box type the file extension of interest; then click on the “size” column to sort by file size.