Assuming that they are looking at it at the time, I would use "this".
My friend sends a weird picture to me and I send it to my other friends. I say:
My friend just sent it/this/that to me and I couldn't stop laughing.
Are all three okay?
I would use "this" the first time and follow it with "it" if there are further sentences.
My friend sent this to me this morning. I couldn't stop laughing. I thought you'd love it so I'm sending it to all of you.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.
Yes, but they've already seen the picture because I sent it to them, so would it be completely wrong here?
My friend just sent it to me and I couldn't stop laughing because he finds the weirdest things!