More useful advice from the folks at Buffer:
In general, here are the best sizes for sharing images on social media.
Facebook – 1,200 x 628
Twitter – 1,024 x 576
Instagram – 1,080 x 1,080
LinkedIn – 552 x 368
Pinterest – 600 x 900
Google+ – 800 x 320
And here is "the Essential Social Media Design & Sizing Cheat Sheet" from omnicore:
Christian Ebernickel discusses why UTM parameters are are not suitable for tracking internal campaigns and proposes using ITMs instead.
ITM Parameters At A Glance Link
Drawing on the UTM parameters, we’ll use the following ITM parameters to track internal marketing campaigns:
This identifies the source of the traffic. In the case of internal ads, this is usually your own domain. However, if you employ cross-domain tracking or different ad servers, different traffic sources can appear in this field.
This is the medium of the internal ad; for example, a banner or product recommendation.
This is the name of the internal marketing campaign.
This is a parameter to differentiate between similar content, or links in the same ad; for example, text_link or banner_468x60.
- This is the search keyword that triggered the internal ad. Alternatively, it could be a keyword to categorize the ad by content.