Also if you're in the US and post a photo that includes an envelope that was mailed to you, there's almost always a postal sorting barcode (that thing that looks a bit like |'•|,,'|, etc) on it that can ID your unique mailbox/address (ZIP+4 and Delivery Point code). The data to do this is publicly available, and even if the barcode can't be scanned, it can be manually decoded because there are only four different bars (short, high, low, and tall).

Black out your entire address and the entire barcode. Seriously, it's super easy to figure out your address, and from there it's not usually hard to find your name. Name and address often means phone, SSN, etc.