What if that sentence were uttered AFTER the picture was sent?
Your first sentence, "this is the last time I send this picture," could be said before you send it or while you send it (like as an email or a text).
You'd probably need to reword it a bit and add some more if you said it after the fact:
"The last time I sent the picture was it/was the final time, I'm not going to send it again," or even "that was the last time sending you the picture."
Also, I can think of some instances where I've heard it said like this, but I'm not sure how common or correct it would be:
"That was the last time I'm going to send the picture."
(not a teacher, just a language lover)