One of the major parts of social media platforms like Twitter, Facebook and pixiv is the square icon on your profile. A perfect selfie would be great too, but there are many against putting their own faces on the internet. In cases like that, why not use an icon of an illustration of one of your favorite characters! For the people out there like this, pixiv has a collection of free icons you can use.
*When using an icon, do remember to read the caption of the work.