Use 1080 × 1080 for a square, 1080 × 1350 for a 4:5 portrait post, or 1080 × 1920 for a 9:16 Story/Reel workflow. Choose Fit to show the whole source or Fill to cover the frame with a centered crop.
Start with the destination shape
A pixel size and an aspect ratio answer different questions. The ratio controls shape; the pixels control resolution. The Image Resizer includes practical export presets, but Instagram may still recompress the upload. Keep essential text, faces and logos away from the extreme edges.
Use Fit when nothing can be cropped
Fit scales the entire photo inside the target canvas. A landscape photo inside a portrait post will leave space above and below, filled with the background color you choose. This is the safest option for group photos, product labels and screenshots containing text.
Use Fill for an edge-to-edge post
Fill enlarges the source until every output pixel is covered, then crops equal overflow from opposite sides. Preview the result carefully: a wide photo placed in 4:5 will lose more from the left and right than a nearly portrait source.
Export and check the real file
Choose JPG for ordinary photos, PNG for lossless graphics, or WebP for modern web delivery. The tool encodes the preview and reports its dimensions and download size. Open the downloaded file once before posting to verify that the crop and text remain correct.