9. The computer-implemented method as recited in claim 2 , further comprising: detecting, from amongst the image data that passed the quality check, discrepant images that cause a discrepancy between designations received from the second plurality provider devices and designations assigned by the classifier; sending at least a portion of discrepant image data to the second plurality of provider devices; receiving ratings of at least a portion of the sent discrepant image data from the second plurality of provider devices; applying a secondary quality check to the discrepant image data corresponding to the ratings received from the second plurality of provider devices; and further training the classifier with respect to the discrepant image data that passed the secondary quality check.
2. The computer-implemented method of claim 1 , further comprising: training a classifier to classify one or more images depicting an emotional state, affective state, or action unit associated with the predetermined expression using at least a portion of the image data that passed the quality check; and using the classifier to classify additional image data.