I have the Soviet coat of arms as my profile picture. It is the version from before 1956 so it also has the Karelo-Finnish SSR.

Personally, nearly all my profile pictures are just fictional character i like + bi flag and/or hammer and sickle in the background so idk much in the way of “professional” pfp’s lol but in that scenario I’d probably go with some sort of historical photo of a leftist figure, preferably someone less recognizable to your average lib depending on how “professional” the environment is. As much as i love ol’ joe he was absolutely correct in saying a pile of rubbish would be heaped apon his grave. So pick someone deemed more “sensible”.

When I first got to this place, I had a picture of Chad Jinping:

But then some other people had the same picture, so that lead to some confusion.

I then chose Thomas Sankara as a pfp. No specific reason other than him being based and his smile resembling my own smile in real life.

Can’t help you with your specific request for leftist inspo since my profile pic is a photo of my dogs lol but I can answer the “why do you use it” part:

Because they’re good dogs and they look hilarious in this specific photo. They’re so focused because I was holding a ball and were waiting for me to throw it lol

“Solemn Oath”, Red Army recruitment poster from 1918. Translation here.