True, although as the sibling suggested you can sort by confidence and weed out the edge cases. It's also quicker to go through mostly correct images as you need to make fewer (corrective) interactions/clicks. You can even view eg four thumbnails at once to spot outliers.

> you still need to consider every image

Not necessarily. The classifier will not only tell you whether it sees a rat, but also its confidence. So you can manually classify just the low confidence images, retrain, and repeat until there's none left or you're happy with its detection rate.