Should I attach my resume in a networking email?

this past fall when it got closer to recruiting, I ended up attaching it using this line "Also, I have attached my resume as a conversation piece and if you have any questions about my background."

You're a sophomore... so no, don't waste anyone's time with a resume that says where you may have interned and what clubs you are in.

Attach it if you have any relevant experience

Whenever I went through the recruiting and networking process, I always attached. It's direct and gives the person you're emailing an immediate way to screen you and form a first impression on you (which is what you want, assuming you're a qualified candidate).

Now that I'm on the other side, I prefer when students do this because it allows me to immediately get a feel for them and see if they're even worth my time or if I have any connections with them.

If you do attach it I would say do it as a PDF, not as a word doc.

Went through SA recruiting as a junior this fall. I found that I generally got a better response rate when attaching my resume, and a few times when I didn't bankers specifically asked for me to send it. If you do have some relevant internship already, I don't think it would hurt to include.

I always tell people to attach a resume. I've had alums tell me in the past they only responded to my emails because I had a good profile.