#1: Start With Open Graph Dimensions
The best way to start with is the Facebook open graph image dimensions.
An open graph image is 560 x 292 and can be created using many tools including Adobe products, Canva, PicMonkey and others. There are simple techniques to make your images look great.
Tip: When creating an image, consider adding background layers and text. You can also upload icons and select a color palette. There are many great articles on creating shareable images.
#2: Make Your Text Fit
Here’s the magic trick to make your image look its best across all three platforms.
Make sure you place all of your text within the area shown across all three channels. This provides the best visibility for your image.
With a bit of math, you can figure out the overlapping areas. Here are the measurements you need to note.
When you’re in the image creation software, make sure that all of your text has a 40-pixel buffer on either side and a 10-pixel buffer on the bottom. I cushion mine an extra 2-5 pixels on the bottom and 5-10 pixels on the sides, just for a bit of breathing room. Otherwise, your image touches the edges when it’s published on LinkedIn and Twitter.
If you’re used to making optimized images for all channels, this may feel restrictive at first. But after you’ve done it a few times, you’ll feel comfortable using the new boundaries.
By creating an image with a cushion on three sides, you’ll go from having an image that works on only one channel to an image that appears specifically optimized for each channel it’s shared on.
#3: See How Your Image Renders
Once you have your image, share it on Facebook, Twitter and LinkedIn and see the results.
Here’s an image created with the overlapping parameters:
Here’s how this image shows up across platforms.
No company names were cut off the bottom in Twitter and no text was lost on the sides of the image in LinkedIn. All three channels now render the text in full and the image looks beautiful on all three channels.
How do your images look when shared?
Conclusion
With this simple technique, you can stop creating different images for LinkedIn, Facebook and Twitter. Instead, create one eye-catching image and it will look like it was made specifically for each channel when shared.
Improve your visual marketing across these main social channels so you can stand out.
Source: http://www.socialmediaexaminer.com/optimize-images-across-social-networks/