The present invention provides a photosensitive resin composition for a pad protective layer that includes (A) an alkali soluble resin, (B) a reactive unsaturated compound, (C) a photoinitiator, and (D) a solvent. The (A) alkali soluble resin includes a copolymer including about 5 to about 50 wt % of a unit having the Chemical Formula 1, about 1 to about 25 wt % of a unit having the Chemical Formula 2, and about 45 to about 90 wt % of a unit having the Chemical Formula 3, and a method of making an image sensor using the photosensitive resin composition.