Hi Theodore,
Using a funny photo of yourself with the two pound dumbbells on your dating profile isn’t cringey at all.
It is you not taking yourself too seriously. If anything, it would be a nice counter to any other gym pics that you have on your dating profile that show you really focused on your workout.
It lets people see that you aren’t just about working out. You also have a lighthearted side to you and you aren’t afraid to make fun of yourself. This makes you so much more personable to people, increasing the likelihood that they like your dating profile.