You can Develop photos in Lightroom Classic to share to Instagram based on Instagram aspect ratio and ideal post sizes. To do so, follow the steps below:
- In Lightroom Classic, choose a photo.
- Go to Develop > Crop Overlay.
- Choose the aspect ratio you want (1 x 1, 1.91 x 1, or 4 x 5) and click Done.
- Right click > Export and choose the Instagram preset that corresponds to your aspect ratio.
Andrew Aveley. (2021, September 21). Instagram photo size—How to crop for instagram in lightroom. https://www.youtube.com/watch?v=myZ4kC15VlU