Resize a photo for Instagram
Instagram crops whatever you give it. Upload at the exact ratio instead and you decide the frame, not the app.
Upload at the ratio, not at the crop
Instagram does not respect your framing. Feed it a 3:2 photo and it will centre-crop to 4:5 or 1:1 depending on where you tap, usually taking the top of someone's head with it.
The fix is to crop deliberately before uploading: pick the slot you want, resize to those exact pixels, and the app has nothing left to decide. Portrait (1080 × 1350) gets the most screen area in the feed, which is why it has become the default for anything that is not a landscape shot.
Stories and Reels are 9:16 — 1080 × 1920. Leave the top 250 px and bottom 250 px relatively clear if you plan to add text or stickers, because the interface sits on top of them.
Questions
Does resizing lose quality on Instagram?
Instagram re-compresses everything you upload. Sending exactly 1080 px wide means it has less work to do, so the result is usually sharper than uploading a 4000 px original.
Can I post a photo that is not square?
Yes — portrait and landscape both work. Choose the slot first, then resize to its ratio.
Should I use PNG or JPG?
JPG. Instagram converts to JPG anyway, and PNG files are much larger for no benefit on a photograph.