BACKGROUND Dermatology being a visual branch, there is a need to add a visual element in learning and assessment of dermatology. This study compares the utility of image-based assessment (IBA) as a new tool compared to routinely used semi-structured viva (SSV) in dermatology formative assessment at undergraduate level. METHODS Comparison was made between batches of students in year 2018 who underwent clinical posting term ending assessment by IBA with the retrospective cohort of batch of students in year 2015 who underwent assessment by SSV. The students' marks in this assessment and their attendance were collected. Feedback was taken from batch of students who had undergone IBA assessment. Faculty feedback was also taken. RESULTS Correlation of attendance with marks was higher in IBA batch compared to SSV. IBA is better able to assess the diagnostic skills which requires visual element and prescription writing skill. SSV can do an authentic assessment of clinical reasoning skills. IBA had higher variability in marks allotted to students suggesting that it was more objective tool whereas with narrow range of marks SSV was found to be more subjective. Both IBA and SSV had similar acceptability by students and faculty. IBA was more resource intensive at preparation stage while SSV was so in conduction stage. IBA had better educational impact, as it promoted learning through exposure to actual patients. CONCLUSIONS IBA fared better in terms of validity, reliability, acceptability, and educational impact. In terms of feasibility IBA and SSV had differing challenges.