A practical guide to your next decision
A practical field guide to image size, composition and file weight. Read from start to finish, or jump straight to the decision you need to make.
Worked example and sample files
Fit mode keeps the entire image and preserves its aspect ratio. Cover mode fills a requested rectangle and discards the edges that do not fit. Padding mode keeps the entire image inside an exact canvas and adds space around it. Stretching would change the proportions of faces and products, so this editor does not use stretching as a substitute for these modes.
Work through an example
For a 4032 × 3024 image and a 1920 × 1080 request: fit gives 1440 × 1080; cover gives 1920 × 1080 with the top and bottom cropped; padding gives 1920 × 1080 with 240 px of space on each side. Download all three examples and compare the mountain and tree.
- Open the relevant tool below and choose a supported image. Check the original dimensions and bytes before changing anything.
- Set the dimensions and fitting mode for your destination. Enable enlargement only if you accept that it cannot restore missing detail.
- Process the image, switch between Original and Result, and check the final pixel dimensions and exact bytes. If a target is not met, change an allowed constraint and run again.
Check before you download
A centered crop can cut off a subject near the edge. Move the horizontal and vertical focus, or use numeric crop coordinates. The editor does not detect faces automatically.
Try the files yourself
The following original geometric illustration and exports are supplied with this project. These are actual files, not estimated savings. The exported examples use JPEG quality 85. Your own images will have different byte counts; compare details as well as weight.
| Result | Width × Height | File size |
|---|---|---|
| Original | 4032 × 3024 | 225354 bytes |
| Try a sample image | 1200 × 900 | 36438 bytes |
| Fit within bounds | 1440 × 1080 | 41113 bytes |
| Fill & crop | 1920 × 1080 | 44272 bytes |
| Add padding | 1920 × 1080 | 44602 bytes |
Choose your next step
Exported images remove EXIF, GPS and XMP metadata. Processing uses SDR/sRGB.
Choose what changes: scale, frame or surrounding space
Imagine a poster with a title near its top edge. Fit keeps the title and poster proportions but may leave an output smaller than the requested rectangle. Cover fills the rectangle but may remove the title. Padding keeps the title within an exact canvas by adding space. Before choosing, ask which promise the project needs. A technically correct crop is the wrong answer when the removed text is essential.
Compare the downloaded examples, then run the same experiment with a portrait. Different source ratios change which edges cover removes and where padding appears. Do not memorize one margin value as a universal rule. The relationship between source ratio and canvas ratio determines the result.
Fit, cover and padding: three different promises
Fit mode promises a complete image inside a bounding box. Cover promises a filled rectangle and accepts discarded edges. Padding promises an exact canvas while keeping the complete image inside it. These modes answer different questions. Choosing the wrong one can produce a technically valid download that still fails your layout: too narrow, too cropped or surrounded by unexpected empty space.
Use the same source to compare the modes. Our 4032 × 3024 illustration is 4:3, while 1920 × 1080 is 16:9. Fit produces 1440 × 1080. Cover fills 1920 × 1080 by removing the top and bottom. Padding puts the 1440 × 1080 image on a 1920 × 1080 canvas, leaving 240 pixels on each side. The source did not change; your definition of a successful output did.
Crop around the subject, not automatically around the center
A crop selects which information belongs in the final frame. The center of the source is only a starting point: a face, product label or horizon may sit elsewhere. Look at the subject and leave enough breathing room around it. For a wide cover image, check both the top and bottom. For a square made from a landscape, check the left and right before downloading.
Use the numeric rectangle when placement needs to be repeatable. X and Y locate its upper-left corner in the normalized source; width and height describe the selected area. Arrow keys can move the selection, and the focus controls adjust cover placement. These controls do not recognize faces automatically. A crop that is mathematically centered still needs a human composition check.
Aspect ratio protects faces, products and lettering
Aspect ratio is width divided by height. A 4000 × 3000 photograph has a 4:3 ratio; a 1200 × 800 photograph has a 3:2 ratio. Changing both sides by the same scale factor preserves this relationship. Changing them independently can stretch a face, widen a bottle or turn a circle into an oval. This editor uses proportional fitting, cropping or padding instead of treating distortion as an acceptable resize.
When you only know the desired width, leave the other side automatic. For a 4000 × 3000 source, width 1600 gives height 1200. If the destination instead needs 1600 × 900, you are also asking for a new ratio. Decide whether the missing space should come from cropping the image or adding space around it. A ratio decision is a composition decision, not just a multiplication.
The concepts behind this page
These relationships explain why changing one setting can affect another. Use them to identify which constraint matters most for your image.
- Crop
- A selected source rectangle that leaves the remaining edges out of the export.
- Padding
- Added canvas space around an image whose proportions stay intact.
- Aspect ratio
- The relationship between width and height, such as 4:3 or 16:9.
- Output canvas
- The complete exported rectangle, including any padding.
- Pixel dimensions
- The width and height of the decoded image grid.
- Pixel dimensions determine the proportions described by Aspect ratio.
- Crop changes the framing and can change Aspect ratio.
- Padding adds space to Output canvas.
Questions worth asking before you export
Why is the output smaller than the dimensions I entered?
Fit treats both dimensions as maximum bounds and preserves the original ratio. It can therefore produce a smaller rectangle. Use padding for an exact canvas with the complete image, or cover when you accept removing edges.
Does quality 100 make the export lossless?
No. JPEG quality 100 is still an encoding setting, not a promise of identical source pixels. Resizing itself also changes the grid. Preserve the original when you need an unchanged archive.
Can enlargement recover missing text or faces?
No. Enlargement estimates new pixels and cannot reliably reconstruct details absent from the source. Find a higher-resolution original when those details are important.
Sources and how to verify the examples
The numerical examples on this page come from explicit geometry calculations and the project’s synthetic files. Hypothetical byte counts illustrate acceptance rules; downloadable sample counts describe those specific files. The references below explain the underlying formats and browser export API, not a guaranteed saving or acceptance by another service.
Ready to prepare your image?
Keep the original, choose one clear requirement, and inspect the exported file. A useful result meets its destination’s rules and keeps the details that matter.
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