What is a pixel?
Digital images are made up of small squares, just like a tile mosaic on your kitchen or bathroom wall. A digital photograph looks smooth and continuous just like a regular photograph, it’s actually composed of millions of tiny squares.
Images are usually measured by counting the number of individual pixels (dots/squares of image data) in an inch. Thus the resolution of digital images is often given in “Dots per Inch”(DPI) or “Pixels per Inch” (PPI) and let us know how sharp an images is.
Images for web resolution or print resolution
File size can help you understand what images are useful for printing and what images are best used only on your website. File sizes are in KB (Kilobytes) and MB (Megabytes)
KB = 1,000 bytes
MB = 1,000 kilobytes
What Resolution Should Your Images Be?
Website:
- Pixel Size: About 400–600 pixels wide for a large image; 100–200 for a thumbnail image
- Resolution: 72 DPI
- Approximate file size: JPEG 20–200 KB
Printed in a book or magazine:
- Pixel Size: Multiply intended print size by resolution; e.g. an image to be printed as 6” W x 4” H would be 1800 x 1200 pixels.
- Resolution: 300 DPI
- Approximate file size: 6–10 MB
What’s the difference between 300DPI and 72DPI?
- The difference between 300DPI and 72DPI is found in the amount of pixel information (or dots) for every square inch of an image.
- The more dots/pixels the image contains, the sharper the image will print.
- When printing your images should be 300DPI. Web graphics and online photos should be 72DPI. This low resolution is great for the web and prevents slow load times when a visitor is looking at images on your website.
- Printing = 300DPI
- Web = 72DPI
Common Image Sizes for Social Media & Marketing
Facebook:
- Facebook profile image: 180 x 180px
- Facebook cover photo image: 820 x 312px
- Facebook post: (Timeline/news feed) 1200 x 630px
- Facebook Event Image: 1920 x 1080px
Instagram:
- Instagram profile image: 110 x 110px
- Instagram feed image: 1080 x 1080px
- Instagram story image: 1080 x 1920px
Email Marketing:
- EDM Electronic Direct Mail: under 600px wide
Websites:
- Most websites recommend using images that are smaller than 500 KB and between 1500 - 2500px wide.
- Whilst large images sizes are fantastic for print quality projects, using unnecessarily large images on your website will increase load times and affect your site performance.
Need to decrease a file’s size? You can use tools like TinyPNG.
