Thanks for your attention! Ignore this question for now as it doesn't seem a length issue as I have just tried with a certain bunch of URLs that we are facing a problem with while not with another bunch. Will update the question above once I have more clarity.
Note: All links used in this post are hypothetical to explain the issue. Can't share actual links as the site is under development and confidential.
Suppose I try to post a shortened link in a facebook post such as http://tinyurl.com/j9w7uth, which translates to something like this: https://www.example.com/product-detail-page.html. The issue is the preview image. The preview image has a url that is being truncated. The error message while posting in facebook is such -
This happens only with products, and only when the products have images that have been set up through Magento. If it is an external image, as mentioned above, with a url along the lines of https://d3v0wwxsdfl9f8.cloudfront.net/media/catalog/cdn/e823.jpg, there's no issue.
If the image has been uploaded through Magento (which only happens on product pages) the image will have a url along the lines of:
And facebook will truncate that url http://d3v0wwxsdfl9f8.cloudfront.net/media/catalog/product/cache/1/thumbnail/600x/17f82f742ffe127f42dca9de82fb58b1
This happens whether or not you use a url shortener, because the shortener does not shorten the preview image url. It shortens the url of the page, which has no problem.
Have read about facebook's handling of such issues when reported but did not want it all that encouraging, hence want to understand if there could be a way we could shorten the auto-generated URL and/or workaround this issue within Magento itself. If nothing is possible then will have to knock on fb's door.