
Toward Trustworthy Portrait Editing: Evaluation of Demographic Misrepresentation in I2I Models
Under Review, 2026
Abstract
Instruction-guided image-to-image (I2I) editors are increasingly entering consumer and professional visual workflows, where trustworthiness depends not only on prompt compliance but also on equitable preservation of identity-relevant attributes. We formalize two failure modes Soft Erasure, where requested edits are weakly realized or silently suppressed, and Stereotype Replacement, where edits introduce unrequested, stereotype-consistent demographic attributes and evaluate them across three recent open-weight editors on 5,040 edited portraits. We find that 62-71% of outputs exhibit skin lightening, with Indian and Black source portraits affected at 72-75% compared with 44\% for White source portraits, a pattern consistent with output-level drift toward lighter or more White-presenting appearances when identity constraints are underspecified. In a mitigation case study, prompt-level appearance constraints reduce race-change scores for non-White source portraits by up to 1.48 points, with negligible change for White source portraits, without modifying model weights. Together, these findings show that identity preservation is not a uniform property of I2I portrait editing systems, but an unevenly distributed trustworthiness failure with direct social consequences. At deployment scale, such silent distortions can shape AI-mediated self-representation and reinforce representational disparities. We introduce a controlled audit protocol for fairness-aware evaluation and governance of generative editing systems.







