The 4:5 advantage
Social feeds are a competition for vertical space on a phone screen. A square post at 1080 × 1080 fills the width; a 4:5 portrait at 1080 × 1350 fills the width and 25% more height. That extra height means your image stays on screen longer as people scroll, which is why photographers, brands and creators widely use 4:5 for feed posts. It is also close to the 3:4 shape of most phone photos, so very little needs to be cropped.
Framing tips
- Portraits: keep a little space above the head; the top and bottom are where cropping happens with 3:4 originals.
- Landscape photos: a 3:2 or 16:9 landscape loses a lot of width when cropped to 4:5. Consider “Fit and pad” with a white or matching colour, or choose a different image.
- Text overlays: keep text away from the very bottom of the image, where the platform may place captions or buttons in some views.
How it works
Each image is decoded in a background Web Worker, rotated according to its EXIF orientation, and then the centre region with a 4:5 ratio is selected (for “Crop to fill”). That region is resampled to 1080 × 1350 using Lanczos3, a high-quality filter that keeps edges sharp. With “Fit and pad”, the whole image is scaled to fit inside and centred on a canvas filled with your chosen colour. Nothing is uploaded.
Choosing the output format
Instagram re-encodes every upload as JPG. Uploading a high-quality JPG means the second compression has less work to do and the final post looks closer to your original. Choose JPG in the format menu if your input is HEIC, PNG or WebP.
Related sizes
For the classic square, use 1080 × 1080. For Stories and Reels, use 1080 × 1920. The social media resizer lists every platform size in one place.