Instagram aspect ratios and cropping

Postbean does not crop, resize or re-encode your images. Whatever you upload is what Instagram receives, and Instagram applies its own rules from there.

That is worth knowing, because it means the crop you see on Instagram is Instagram’s decision, and the only place to change it is before you upload.

What Instagram accepts

Instagram’s publishing API takes aspect ratios between roughly 4:5 (portrait) and 1.91:1 (landscape). An image outside that range gets fitted by Instagram — usually cropped from the centre.

The safe choices:

• 1:1 square — works everywhere, never surprises you.
• 4:5 portrait — the tallest the feed allows, and the most screen space.
• 1.91:1 landscape — for wide images that would look wrong cropped square.

Carousels with mixed ratios

In a carousel, the first image sets the shape. Every image after it is fitted to match, so a square first slide followed by a tall one means the tall one gets cropped.

If the carousel matters, export every slide at the same ratio before uploading. It is the single easiest way to avoid a surprise.

Checking before you publish

The Preview panel in the composer renders the post the way Instagram will show it. If a slide looks wrong there, it will look wrong on Instagram — fix it in your editor and re-upload rather than publishing and hoping.

Reels and stories

Reels and stories are vertical, 9:16. A landscape video published as a Reel is letterboxed by Instagram, so export vertical when you know it is going to Reels.