Image Size refers to two parameters:

  1. Dimensions (e.g., 1024 by 680 pixels)
  2. File size ( e.g., 350 kilobytes)

Both parameters are important since a smaller image (by dimensions) doesn’t always mean a smaller image file size. At the same time smaller image file size doesn’t always mean worse image quality or smaller image by dimensions.

Proper Image File Size

Big file size can lead to slower page load which in its turn can lead to higher bounce rate, bad user experience and downgrade in Google ranking.

What is bounce rate?

Bounce rate is the percentage of visitors to a particular website who navigate away from the site after viewing only one page.

Too small image file size can make image quality unattractively low.

What is the proper image file size?

An image file size is better not to be over 500 kilobytes. The minimum file size is limited only to what you find visually appealing.

Proper Image Dimensions

Proper image dimensions are more complicated to define.

The short answer is that any image dimensions which look good for users are ok.

The numbers below are usually recommended to user but not a must.

Website images:

  • Full-width images should be 2400×1600 px
  • Inside content images: horizontal – max width 1500 px, vertical – max width 1000 px
  • Slideshow images should be 1500 px height
  • Blogpost image – 1500 px width
  • Favicon image – 300×300 px

Facebook images:

  • Facebook profile pic180×180 px
  • Cover image 820×312 px
  • News Feed Post940×788 px
  • Feed ads1200×628 px
  • Facebook Stories1080×1920 px
  • Facebook Event Cover Image1920×1080 px

Instagram images:

  • Instagram profile pic110×110 px
  • Post images – 1080×1080 px
  • Oblong posts (portrait or landscape) – 1080×1350 px
  • Feed ads1080×1350 px
  • Stories Posts and Ads1080×1920 px

Twitter images:

  • Twitter profile pic400×400 px
  • Cover image – 1500×500 px
  • Tweet images1024×512 px
  • Twitter card and Ad Image800×320 px

LinkedIn images:

  • LinkedIn profile pic400×400 px
  • Cover image – 1536×768 px
  • Feed and Sponsored post image1200×627 px

Pinterest images:

  • Pinterest profile pic165×165 px
  • Pins and Promo Pins – 564×846 px (Pinterest recommend 600×900 px)