Standard Operating Procedure for Recommended Image Size for Social Media:

LinkedIn Image Sizes

1.LinkedIn image sizes for profile photos: 400 x 400 pixels or larger (recommended)

2.LinkedIn image sizes for profile cover photos: 1584 x 396 pixels (recommended)

LinkedIn image sizes for company pages:

1. Company logo size: 300 x 300 pixels

2. Page cover image size: 1128 x 191 pixels

3. Life tab main image size: 1128 x 376 pixels

4. Life tab custom modules image size: 502 x 282 pixels

5. Life tab company photos image sizes: 900 x 600 pixels

6. Square logo: At least 60 x 60 pixels

7. LinkedIn image sizes for blog post link images: 1200 x 627 pixels (recommended)

8. LinkedIn Stories image sizes:

Aspect ratio: 9:16
Resolution: 1080 x 1920 pixels
File types: JPEG and PNG

9. LinkedIn image sizes for ads:

Company logo size for ads: 100 x 100 pixels
Spotlight ads logo size: 100 x 100 pixels
Spotlight ads custom background image: 300 x 250 pixels
Sponsored content images: 1200 x 627 pixels (1.91:1 aspect ratio)
Sponsored content carousel images: 1080 x 1080 pixels (1:1 aspect ratio)

Facebook image sizes

1. Facebook image sizes for profile photos: 170 x 170 pixels (on most computers)

Display size desktop: 820 x 312 pixels
Display size smartphone: 640 x 360 pixels
Minimum size: 400 x 150 pixels
Ideal file size: Less than 100KB

2. Facebook image sizes for posts and timeline photos:

Recommended size: 1200 x 630 pixels
Minimum size:600 x 315 pixels

3. Facebook image sizes for event cover photos: 1200 x 628 pixels (recommended)

4. Facebook image sizes for Facebook Stories: 1080 x 1920 pixels (recommended)

5. Facebook image sizes for ads:

Sizes for Facebook Feed ads:At least 1080 x 1080 pixels. Minimum size 600 x 600 pixels. Ratio 1.91:1 to 1:1. Maximum file size of 30 MB.
Sizes for Facebook Right Column ads: At least 1080 x 1080 pixels. Minimum size 254 x 133 pixels. Ratio 1:1. (Remember: These are a desktop-only ad format.)
Facebook image sizes for Instant Articles: At least 1080 x 1080 pixels. Ratio 1.91:1 to 1:1. Maximum file size of 30 MB.
Image sizes for Facebook Marketplace ads: At least 1080 x 1080 pixels. Ratio 1:1. Maximum file size of 30 MB.
Image sizes for Facebook Search: At least 1080 x 1080 pixels. Minimum size 600 x 600 pixels. Ratio 1.91:1 to 1:1. Maximum file size of 30 MB.
Facebook image sizes for Sponsored Messages: At least 1080 x 1080 pixels. Ratio 1.91:1 to 1:1. Maximum file size of 30 MB.
Sizes for Messenger inbox ads: At least 1080 x 1080 pixels. Ratio 1:1. Minimum size 254 x 133 pixels. Maximum file size of 30 MB.
Sizes for Messenger Stories ads: At least 1080 x 1080 pixels. Ratio 9:16. Minimum width of 500 pixels

YouTube image sizes

1. YouTube profile photo size: 800 x 800 pixels (recommended)

2. YouTube banner image size: 2048 x 1152 pixels (at minimum)

Aspect ratio:16:9
Minimum area for text and logos without being cut off:1235 x 338 pixels
Maximum file size: 6MB

3. YouTube video size: 1280 x 720 pixels (at minimum)

4. YouTube thumbnail size: 1280 x 720 pixels

Quora Image Size

1280 x 720 upwards, anything less shouldn't really be used unless you're targeting strictly mobile users. Don't go too big as you need to respect page load speed which isn't going to be your strong point if your shoving 20MB images on your users.