Humour is always a little bit of a dangerous thing to try. Done right, it makes things great, but done wrong it can really mess them up. Here, you're making it far more dangerous in two important ways. First, you're operating in a culture you didn't grow up in, so you're not sure if things will be seen as funny or not, and second, you plan to do this first, before the audience has any context to be able to realize "oh, it's a joke!"
I was at a talk once where the speaker opened by crunching a hidden plastic cup loudly on the back of his neck while saying "AAAH! UUrrrrgh!" and so on as though it was his neck being hurt or damaged, and then when people were perturbed (and I believe one got up to help him) showing the cup and saying it was just to lighten the mood. Several people were angry about being fooled into feeling compassionate towards him and one told me afterwards she really didn't listen to the talk at all as a result. This powerfully demonstrated to me how risky it is to "open with humour" when people don't know anything about you.
If you have a funny photo that you would really love to share, I suggest waiting until the very end, perhaps just before the Q&A. At this point the audience knows you are good, knows you're a nice person, and has learned what they came to learn. You can then say something like "of course, we can't take this all so seriously all the time" and show the funny picture. This is still risky. If the picture would actually upset or offend some people, don't do it. Assuming it's harmlessly funny, putting it at the end leaves people with a warm feeling that you're a real person, and is less likely to bother people than before they have heard anything else from you.