Didn't want to upload that same image from Reddit's furry_irl that gets posted each year, so I made my own. This is the only day this post will be accurate. Have a great 6/21 everyone!
Alt text (accessibility)
A pixel art rendition of Esix, the mascot of E621, a website that hosts and tags furry art which is often explicit. Esix is an anthro feline like creature who has a literal hexagon for a face, a blue body, white ears with yellow tips, and yellow fingers. Portions of them, such as the fingers and ears, float above the body unconnected.
The top of the image has text which says It's June 21st, where June is in a yellow ribbon styled rectangle, denoting the month portion of a simple calendar. The 21 is in a white square box under it, like a daily calendar you'd rip the page off of.
The bottom of the image has Esix looking directly at the viewer with partially closed eyes and a big smile. Their right (your left) hand is pointing upward at the date. Their opposite side has Esix's yellow flame tail visible.
This date is relevant because with dating methods which use Month/Day/Year or Year/Month/Day, it makes the number 6 21, which is the number for E621. It is mentioned in furry circles when it comes around each year.
The background is darker blue, with a series of even darker hexagon rings that form a hexagon in the center. There is a dotted white outline which runs across the entire border of the image.
https://youtu.be/DtxNkADGVkY?si=dDUVimjwlwvIYE-e