How to resize an image by pixels
Upload the image. The width and height fields start with its current dimensions. Type a new width, and with Keep aspect ratio checked the height is calculated for you, rounded to the nearest pixel. Or type a height and let the width follow.
To set both values independently, uncheck Keep aspect ratio. Be aware that if the new shape doesn't match the original, the image will be stretched or squeezed to fill it. Each side can be between 1 and 10,000 pixels.
Common pixel sizes
For websites, 1200 to 1600 pixels wide covers most content images and 1920 pixels suits full-width banners. For email newsletters, about 1200 pixels wide displays sharply at a typical 600-pixel layout width. Profile photos are usually square, between 400 and 800 pixels. Online forms often state their own sizes, so check the instructions first.
If you are not sure, measure where the image will appear and make it about twice that width so it stays sharp on high-density screens.
Pixels vs inches and DPI
Screens only care about pixels. Inches and DPI only matter when printing: at 300 DPI, a 1800 by 1200 pixel image prints at 6 by 4 inches. If a form asks for a size in inches or centimeters, multiply by the DPI it mentions to get pixels, then enter those numbers here.
Upscaling and output quality
Typing a size larger than the original enlarges the image. Lanczos resampling keeps the edges smooth, but it can't invent detail, so a 500-pixel photo stretched to 2000 pixels will look soft. When a site asks for a minimum width, enlarge only as much as you need. The quality slider controls compression for JPG and WebP output and starts at 85 percent.