How to Change the Resolution of a Picture: Pixels, DPI and File Size Explained
imgmend Team
AI Image Tools
Changing resolution can mean three different things: pixel dimensions, DPI, or file size. Here is how to make a picture smaller or larger on Windows, Mac, Photoshop and in your browser.
To change a picture's resolution, change its pixel dimensions (width × height): shrink it with any resize tool, or enlarge it with an AI upscaler such as imgmend, which rebuilds detail instead of just stretching pixels. DPI only changes how large the picture prints, and file size is a separate setting controlled by compression.
| You want to change | What to adjust |
|---|---|
| How sharp it looks on screen | Pixel dimensions (width × height) |
| How big it prints | DPI (pixels per inch) together with the pixel dimensions |
| How many MB it takes | Compression quality and dimensions |
Pixels, DPI and File Size: What Is Different
- Pixel dimensions are the real resolution, for example 1920×1080. More pixels means more detail can be shown.
- DPI or PPI is a label that says how many pixels go in each inch when printing. Changing it alone does not add detail. See how to increase image DPI.
- File size is how much storage the file uses. It depends on the pixel dimensions, the format and the compression.
How to Make a Picture Smaller (Lower the Resolution)
Windows (Paint): open the picture in Paint, choose Resize and Skew, pick Pixels, keep Maintain aspect ratio ticked, enter a new width and save.
Mac (Preview): open the picture, choose Tools → Adjust Size, set the width and height in pixels with the proportions locked, and save.
Photoshop: choose Image → Image Size, tick Resample, set the new dimensions and export.
In your browser: imgmend's compressor has a max-dimension setting plus a quality slider, so you can reduce pixels and file size together and see the result before downloading.
How to Make a Picture Larger (Increase the Resolution)
Enlarging with a normal resize stretches the existing pixels, so the picture gets softer. An AI upscaler predicts plausible new detail as it enlarges.
- Open imgmend.com/upscale-image and upload a JPG, PNG or WebP image (up to 10 MB).
- Run the 2x upscale and wait about 10–30 seconds.
- Compare before and after, then download the PNG.
Free use is 3 images per day with no account, and free downloads carry a small watermark that Pro removes. Images above roughly 2 megapixels are scaled down before upscaling, so very large photos do not come out larger than the original. For a step-by-step on target sizes see how to convert a picture to HD and how to make an image 4K.
Keep the Proportions
Always lock the aspect ratio when you resize, otherwise people and objects look stretched. If you need a different shape, crop first and resize second. If a picture ends up distorted, see how to stretch an image without distortion.
Frequently Asked Questions
How do I change the resolution of a picture?
Change its pixel dimensions with a resize tool such as Paint, Preview, Photoshop or an online compressor, or enlarge it with an AI upscaler.
Does changing DPI change the resolution?
Not the pixel resolution. DPI only sets how large the picture prints; the pixels stay the same unless you resample the image.
How do I resize a PNG?
Use any resizer that accepts PNG: Paint or Preview for a quick resize, or imgmend's compressor to reduce dimensions and file size together. PNGs with transparency keep their transparency.
Can I increase resolution without losing quality?
An AI upscaler makes the picture larger while keeping it looking sharp, but it cannot restore detail the original never captured.
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