Dimensions
Resize or crop? Change image dimensions without stretching
By ResizeFox · Published
Resizing changes the number of pixels. Cropping removes part of the composition. Adding a canvas preserves the whole picture with space around it. Choose between these operations before entering a width and height, especially when moving from a landscape photo to a square post or vertical Reel.
Quick reference
| Use | Size or purpose | Note |
|---|---|---|
| Landscape example | 1200 × 800 px | 3:2 |
| Proportional reduction | 600 × 400 px | 3:2 |
| Square composition | 800 × 800 px | 1:1 |
Step by step
- Find the original width and height. Divide width by height to understand its shape; 1200 ÷ 800 = 1.5, or 3:2.
- Compare that ratio with your destination. If they match, resize directly with Maintain aspect ratio enabled.
- If the ratios differ, crop in an editor or place the entire photo on a canvas matching the destination. ResizeFox does not currently crop or add layout margins for you.
- Upload the prepared image to the resizer. Enter one dimension and check that the other updates to the expected value.
- Preview the result, download it and check that faces and round objects keep their original proportions.
Worked example: a square product card
To turn a 1200 × 800 photo into a square by cropping, retain an 800 × 800 region and remove 400 pixels of total width. A centered crop would remove 200 from each side, but the subject may need an off-center crop. After that, resizing to 600 × 600 preserves the square shape.
If no part of the photo can be removed, fit it inside a square canvas instead. At 600 pixels wide, the full photograph becomes 600 × 400, leaving 200 pixels of vertical space in a 600 × 600 canvas. A layout editor can divide that into 100 pixels above and below.
What happens when you unlock the ratio
Entering 600 × 600 directly for a 1200 × 800 source applies different horizontal and vertical scale factors. A circle becomes an oval and a product changes apparent shape. The tool can do this, but it is not a substitute for deciding which area to crop.
Keep the ratio locked for portraits, products and identity documents. Unlocking it is mainly useful when distortion is intentional. If exact dimensions and undistorted content are both required, prepare the matching crop or canvas first.
Pixel dimensions do not determine file size
Two 600 × 600 images can have very different file sizes because of their content and encoding. Set the composition and dimensions first, then address any byte limit separately. A file-size tool may reduce dimensions further, so recheck both requirements after compression.
Also remember that upscaling cannot recover detail that was absent in the source. Keep your high-resolution original and export new copies for each destination instead of repeatedly resizing the same small download.
See the tradeoffs yourself in the Image Compression Lab: compare text, gradients and transparent graphics with downloadable results.