/01 Cropping to the dimensions each platform expects
Crop an image to the sizes Instagram, Bluesky and Threads actually use, with the aspect ratios preset so you are not looking them up or guessing. You choose what stays in frame rather than letting an algorithm centre-crop it for you.
Export and post, with the composition intact.
/02 Why cropping yourself is worth the extra step
Automatic cropping is indifferent to your subject. It will cut heads off group photographs, remove the text from a graphic and centre on empty background, because it is working to a rectangle rather than to meaning.
Uploading at the right ratio also avoids a second round of recompression — the platform re-encodes anything it resizes, and doing the resize yourself keeps more detail. Keep important content away from the very edges, since some views crop slightly further than the nominal ratio.
/03 Instagram photo sizes and ratios
Before you resize an image for Instagram, pick the shape. Instagram accepts four, and choosing the right one matters more than the exact pixel count. Square posts are 1:1, ideally 1080 × 1080 pixels. Portrait posts are 4:5 at 1080 × 1350, and they take up the most room in the feed, which is why most photographers default to them. Landscape posts are 1.91:1 at 1080 × 566. Stories and Reels are 9:16 at 1080 × 1920.
Instagram displays images 1080 pixels wide. Upload something larger and it is scaled down; upload something narrower and it is stretched and looks soft. This cropper cuts your photo to the exact ratio at its full original resolution, so Instagram only ever has to scale it down cleanly, never guess at a crop of its own. The same tool includes the Bluesky and Threads ratios.
/04 Resizing for Instagram without cropping
Cropping always removes something. When a photo cannot lose its edges, such as a group shot, a wide landscape or artwork, place it on a canvas instead. The Matte Generator fits the entire image inside a square, portrait or story frame, filling the spare space with a white border, a solid colour, a blurred copy of the photo or a gradient. Instagram then receives an image that already has the right shape, so nothing gets cut.