The most common image-resize request is something like: "must be 800x600 pixels, JPEG, under 500 KB." Or: "profile photo must be square, maximum 2 MB." Or: "print size 10x15 cm at 300 DPI." Each of those is a slightly different problem and requires a slightly different approach.
Pixels, inches, and DPI - which one actually matters?
The physical size (cm, inches) of an image only matters when printing. On screen, only pixel dimensions matter. DPI (dots per inch) is the link between the two: an image that is 3000x2000 pixels printed at 300 DPI comes out 10x6.67 inches.
For digital uses - websites, forms, email, social media - ignore DPI and focus on pixel dimensions and file size. For print, use DPI to calculate the pixel dimensions you need before resizing.
Aspect ratio: the thing most people accidentally break
An image has a natural width-to-height ratio. A typical phone photo is 4:3 or 3:2. If you resize to dimensions that have a different ratio - say, forcing a 4:3 photo into a 1:1 square - the image will stretch horizontally or squash vertically. People look unnaturally wide or thin. Objects look distorted.
The two correct approaches are:
- Lock the aspect ratio and resize by one dimension. Set the width to 800 px; the height adjusts automatically to maintain the original proportions. Use this when the form specifies one dimension or a maximum.
- Crop to the target ratio, then resize. If you need exactly 800x600, first crop the photo to a 4:3 area, then resize to 800x600. Use Crop and Rotate Image to do the crop step.
Never just enter different width and height values without locking the ratio - unless the specific use case requires distortion for a reason.
How to resize an image with Pagivo
- Go to Resize Image on Pagivo.
- Upload your image - JPG, PNG, or WebP.
- Enter the target width or height in pixels. The other dimension is calculated automatically to preserve the aspect ratio.
- If you need to resize to a percentage of the original (e.g. 50% smaller), use percentage mode instead.
- Click Process and download. The resized image downloads as the same format as the input.
File size vs. pixel dimensions
A form that says "maximum 2 MB" and "minimum 600 pixels wide" has two separate requirements. Resizing to 600 pixels wide reduces the file size significantly (because there are fewer pixels to store), but a 600 px wide JPG can still be over 2 MB if the quality setting is very high. Conversely, a high-resolution image can be under 2 MB if saved with aggressive compression.
If you hit the pixel target but are still over the file size limit, run the image through Compress Image afterwards. Resize first, then compress - in that order - because compressing a large image and then resizing it sometimes introduces double compression artifacts.
Common resize targets and what they mean
- CV or LinkedIn photo: 400x400 px minimum, square. Crop to square first, then resize.
- Email signature logo: 200-250 px wide at 72 DPI is the typical sweet spot - large enough to look sharp on Retina displays but small enough not to trigger mail client warnings.
- Web hero image: 1200-1600 px wide, then compress to under 300 KB for fast loading.
- Print at 10x15 cm: 1181x1772 px at 300 DPI. Calculate as (cm x 300 / 2.54).