An imaging system may include an image sensor that may be a backside illuminated (BSI) image sensor. The BSI sensor may be bonded to an inactive silicon substrate or bonded to an active silicon substrate like a digital signal processor (DSP). Through-oxide vias (TOVs) may be formed in the image sensor die. A bond pad region may be formed on a light shielding layer to facilitate coupling the light shield to a ground source or other power sources. Color filter housing structures may be formed over active image sensor pixels on the image sensor die. In-pixel grid structures may be integrated with the color filter housing structures to help reduce crosstalk. The light shielding layer may also be formed over reference image sensor pixels on the image sensor die. The TOVs, the in-pixel grid structures, and the light shielding structures may be formed simultaneously.