Do lists of classes take up more space in memory?

[deanhystad]

Since each image always has the same attributes, you could save even more space using slots. Classes that use slots instead of __dict___ provide faster access and have a smaller memory footprint.

class CustomImage(): #my custom image class
    __slots__ = 'name', 'path', 'size', 'ext', 'avg'
    def __init__(self, name, path, size, rgb, ext="png"):
        self.name = name
        self.path = path
        self.size = size
        self.ext = ext
        self.avg = rgb

With slots you cannot add an attribute to the class. You can access or set attribute values, but I could not do custimg.rating = 4 because there is no slot for "rating".
If CustomImage is immutable you could also use a named tuple (import collections).