Whether using social media or posting on a website it is all digital media and a graphic like the one attached is not ADA Accessible and alternative text alone will not make it compliant. There is way too much text in the image for you to be able to describe it in alternative text. While ALT tags need to be descriptive, they also need to be brief. They should not be full sentences or paragraphs. With a limit of about 100 - 125 characters, an ALT tag should provide enough detail for users and search engines to relate the image to the context of the page. In addition, alternative text only benefits assistive technology users and not those with cognitive issues, those who have dyslexia or those with low vision, so its usefulness is limited and all information in the image must be explained.
Many images are considered a complex images and contains many more than 100-125 characters including spaces. These images cannot be adequately explained in alternative text. When an equivalent alternative for a complex image, such as an advertisement, chart, flyer, graph, or map cannot be limited to a succinct alt attribute (see above), then the alternative should be provided elsewhere. The alternative content can often be presented within the context of the page, such as in an adjacent data table or in paragraphs directly above or below the image. The alternative text can also be provided by linking to a separate web page that provides the longer description of the complex image. The link can be adjacent to the image or the image itself could be linked to the long description page. The alternative text for the image should still describe the general content of the image.