In my personal opinion, it is completely inappropriate for shadchanim to ask for full-length pictures. I don’t know which shadchanim you’re going to… no one ever asked me for that, and I met a ton of shadchanim.
I think the idea of sending a picture at all is not tzniusdik. However, I asked a prominent Rov in Flatbush, and he told me that I should send if asked for one. Therefore, I did not have a photo on my resume, but if a shadchan asked for one, then I would send it. This never happened to me, but I would not have sent a picture if the shadchan had told me outright that s/he was going to send it to a boy. If someone had asked me for a full-length picture, I probably would’ve refused and civilly but furiously ended the conversation.
Look, everyone has their own ideas of what’s normal, but I think that full-length pictures is going very far.