"Sizes into" is not a word or phrase on its own, so it is difficult to provide antonyms without knowing which word(s) it is supposed to be. However, if we consider the word "sizes" and the preposition "into" separately, we might come up with some antonyms.
For "sizes," some antonyms might be: reduce, shrink, minimize, or decrease.
For "into," some antonyms might be: out, away from, off, or apart.
For example, if we use "sizes into" to mean "to increase in size," one possible antonym could be "shrinks away from," meaning to decrease in size and move away from something.