About Image Resizing
Image resizing changes the pixel dimensions of an image, making it larger or smaller. This is one of the most common image editing tasks, used for everything from preparing photos for social media to optimizing images for websites.
When to Resize Images
- Web optimization: Large images slow down page load times. Resize to the actual display size (accounting for 2x retina screens) before uploading.
- Social media: Each platform has recommended image sizes. Instagram posts display at 1080x1080, Facebook cover photos at 820x312, LinkedIn banners at 1584x396.
- Email attachments: Resize large photos before emailing to keep file sizes under attachment limits (typically 25 MB).
- Printing: Ensure images have enough pixels for the desired print size at 300 DPI. An 8x10 inch print needs 2400x3000 pixels.
- Thumbnails: Create smaller versions of images for preview galleries, product listings, or video thumbnails.
Maintaining Aspect Ratio
The aspect ratio is the proportional relationship between width and height. When you resize with the aspect ratio locked, changing one dimension automatically adjusts the other to prevent distortion. A 1920x1080 image (16:9 ratio) resized to 1280 pixels wide will automatically be set to 720 pixels tall.
Unlocking the aspect ratio lets you set arbitrary dimensions, which may stretch or squash the image. This is useful when you need to fit a specific size requirement and plan to crop the result.
Upscaling vs. Downscaling
Downscaling (making smaller) generally produces good results because you are discarding pixels. Upscaling (making larger) creates pixels that did not exist in the original, which can make the image look blurry or pixelated. As a rule of thumb, avoid upscaling beyond 150% of the original size for photographic images.