Hello itsumrat,
Facebook, linkedin, and google plus all use open graph tags to generate the content that goes into a shared post. There are several WordPress plugins available to insert OG tags into your site. Here is an article from our support docs referring to the OG tags:
https://support.po.st/hc/en-us/articles/200328796-Set-a-custom-image-description-and-title-for-Facebook-Google-and-LinkedIn
If your site does have OG tags then it is possible that the images you’re trying to share may be slightly off from the guidelines for that specific social platform. Some have image size restrictions, resolution etc.
Please have a look at the doc and let me know if this has resolved your issue.
Po.st Support
