Understand the output
What This Tool Produces
- Original and output pixel dimensions
- Original and output file sizes
- A named resized JPG download
- JPEG quality control
How to Use This Tool
- Open one imageChoose a JPEG, PNG, or still WebP file up to 20 MiB and 40 million decoded pixels.
- Frame and size itChoose a platform such as YouTube or Instagram, pick one of its sizes, then refine the crop. Custom leaves the frame free.
- DownloadAdjust JPEG quality if needed, then download the resized JPG.
Controls and Method
Aspect ratio
Standard covers common photo shapes. Instagram, YouTube, Facebook, LinkedIn, Snapchat, X, and Pinterest each list several platform sizes. Custom leaves the crop free.
Width and height
Creates the exact positive integer width and height entered, up to the 40-million-pixel output limit.
Lock aspect ratio
When width or height is edited, the other dimension is calculated from the crop ratio to avoid stretching.
What to Do With the Resized File
Resizing sets dimensions; it does not decide the byte count. Running the output through the image compressor is what turns a smaller picture into a smaller file, and the two together clear almost every upload limit.
If the source came off an iPhone it may be HEIC, which most upload forms reject outright — convert it to JPG first and resize the result. When several resized images need to travel together, collecting them into one PDF beats attaching them individually.
Pixel Dimensions and Aspect Ratio
An image described as 1920 × 1080 is 1920 pixels wide and 1080 pixels high. Its aspect ratio is 16:9. If both dimensions are changed to a different ratio without cropping, circles become ovals and people look stretched. Locking the ratio or cropping first prevents that distortion.
| Ratio | Shape | Typical use |
|---|---|---|
| 1:1 | Square | Avatars and square tiles |
| 4:3 | Standard landscape | Many cameras and presentations |
| 3:2 | Photo landscape | Camera stills and prints |
| 16:9 | Wide | Thumbnails, slides, and video stills |
| 9:16 | Vertical | Story-style and phone-first canvases |
Resizing Is Not Compression
Resizing changes the pixel grid. Compression changes how that grid is encoded. Fewer pixels often produce a smaller file, but the final size also depends on format, quality, and image detail. Upscaling creates more pixels by interpolation; it cannot reveal detail that was absent from the source.
Practical Uses
- Creating a website thumbnail
- Preparing a product image for a fixed upload slot
- Reducing phone-photo dimensions for email
- Making a profile image or presentation still
Important Limitations
- Upscaling cannot restore missing detail.
- The visual crop editor supports pointer and arrow-key positioning, but it is not a full photo editor.
- Custom output is capped at 40 million pixels.
- The tool does not set print DPI metadata; for web use, pixel dimensions are the important value.
Frequently Asked Questions
How can I resize without stretching?
Keep aspect-ratio lock enabled and enter only one dimension, or crop to the desired ratio before entering both dimensions.
Does making an image larger improve quality?
No. Upscaling interpolates new pixels but does not restore fine detail that the source never contained.
What is the difference between pixels and file size?
Pixels describe width and height. File size describes stored bytes. Format, detail, noise, and compression affect file size in addition to dimensions.
Can I resize by percentage?
This interface exports exact pixel width and height. It does not currently provide a percentage mode.
Does DPI change when I resize?
The tool creates a pixel-based web image and does not preserve or set source DPI metadata. Print size must be planned separately in a print-layout application.