A disabled automatic photo-cropping system by Twitter discriminates on the basis of colour, gender, weight and age, according to the results of an open competition to find algorithmic bias, media reports said.

The microblogging site had, in March, disabled the system as users noted that it favoured white and female faces while auto-cropping images. It then launched an algorithmic bug bounty competition offering prizes of up to USD 3,500 to analyse how the technology incorrectly handles photos, the Verge reported.