If you pay attention to my photographs, I usually sign my name on each image, usually somewhere in the lower right hand corner, shadows permitting. I have a Photoshop action that selects the font tool, and types out my signature in a new layer. I use the Move tool, and drag the signature somewhere not too obnoxious.
Way back in the dark ages of the internet, there was a small company that advertised in various computer magazines. Basically, for $30 (I think), you drew out each letter in the alphabet, upper case and lower case, numbers, some additional characters, and your signature. RAILhead Fonts hand-coded a personal font for you in Macromedia Fontographer, and then sent it to you as a TrueType font on a floppy disc. Since the formats of fonts haven’t changed significantly, I can still use that font on my current computer, over 15 years later.
They did a decent job capturing my scrawl, I do still write almost like this:

A few letters from my handwrithing font.PNG
There are other methods of signing your image – you could scan a piece of paper that you signed and use that as a stamp. Or even take a digital photograph and use that. Or use a tablet, etc. My way is preferable, and scaleable, since fonts are vectors, I can change the size of the signature so that it is proportional to the photograph.
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You Too Will Eventually Disappear