Learn English – the difference between the verbs “shore up” and “prop up”

Formally, we use accuse with an act—we assert that somebody did something reprehensible:

Mary accuses John of failing to lock the door.

But we use blame with the outcome—we assert somebody's responsibility for the undesirable result:

Mary blames John for the robbery. OR
Mary blames the robbery on John.

Informally, however, these distinctions often blur. For instance, if the robbery has already been mentioned, blame may very easily take a for clause which explains why the target is blamed:

Mary's house has been robbed. Mary blames John, for failing [=because he failed] to lock the door.

And accuse may take a complement which expresses a state rather than an act:

Mary accuses John of being responsible for the robbery.

Generally, they mean the same thing - more than average of size, amount, shape, weight and the like.

Though they mean the same, it depends on the context that whether or not you can use those words interchangeably. In your case, they mean the same.

However, if I ignore your example, and focus on your main question 'what's the difference between largest and biggest', I'd say that use them with caution. They are not interchangeable in all cases.

'Big' may also mean 'important' but 'large' does not.

Buying a house was the biggest largest decision I took this year.

There are many other meanings of 'big'. Also, these words are not used in some cases.

Good read is here on the BBC English Learning page.