Image formats
Vector vs Raster Images: Which Should You Use?
What vector and raster images are, what happens when you enlarge each one, which has the smaller file, and which to use for logos, photos, forms and print.
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Short, specific pieces about changing an image's size, in pixels or in kilobytes. They're grounded in what this site's own engine does to the pixels rather than general advice.
Image formatsPNG vs JPG: Which Should You Use?
When to use PNG and when to use JPG, with measured file sizes for photos and graphics, what each format does to quality, and what happens when you save again.
File sizeWhy Is My Image File Size So Large? 6 Causes and Fixes
The six usual reasons an image file is so large, what each one costs on the same test photo, and how to fix the one that applies to you.
Black and whiteHow to Make a Photo Black and White Without Losing the Contrast
Quick ways to make a photo black and white in a browser, on iPhone, Windows, Mac and Photoshop, why some colors turn the same gray, and what the conversion does to file size.
Aspect ratioAspect Ratio vs Resolution in Photos: What Each Edit Changes
What aspect ratio and resolution each describe, which edit changes which, and the order to fix a photo's shape, pixels and file size in.
Aspect ratioHow to Change Aspect Ratio of an Image Without Cropping
Pad, fit or stretch a photo into a new shape and keep all of it: how to work out the exact padding, what each method costs, and which to use for which job.
Passport photosDigital Passport Photo Requirements: Pixels, KB and Format by Country
The pixel, file size and format limits for digital passport and visa photos in the US, UK, Canada and India, from official pages, and what you can safely do to meet them.
FormsPhoto Upload Error: Why Forms Say "File Too Large" and How to Fix It
Why a form says "file too large" or "invalid size", which of four checks your photo failed, and how to get it under the form's limit.
File sizeHow to Reduce Image Size Without Losing Quality
Why a PNG photo is 8 times bigger than the same JPEG, how much pixels and quality really save, and the order to change things in, with measured results.
How-toHow to Stretch a Photo (Without Making It Look Weird)
Learn how to stretch a photo to any size online, on your phone or in free editors, and how far you can stretch before faces and logos start to warp.
4 modesStretch vs Resize vs Crop vs Fit: What's the Difference?
Stretch, resize, crop and fit compared on one 1200×800 photo: the exact numbers, a quick guide to choosing, how to combine modes, and where each goes wrong.