I am trying to click on all of the \"like\" buttons on a webpage. I know how to click on one of them, but I\'d like to be able to click them all. They have the same class name
This is unfortunate, you got two halves of the whole, you cannot find multiple elements by id as ID is unique to a single element.
so combine the iterative method you use with id and the find by elements with classes to get:
like = browser.find_elements_by_class_name('like_picto_unselected')
for x in range(0,len(like)):
if like[x].is_displayed():
like[x].click()
I strongly suspect this will work for you. Please tell me if not.