I am calculating WGS84 coordinates of points in an aerial image, given the WGS84 coordinates of the center of the image and the ground distance width and height (calculated from altitude and lens field of view). Images cover a ground area of no more than 150x100m. Thus far, I have neglected the effects of any coordinate system, and linearly calculated coordinates from the center coordinate.
Some inaccuracy in the coordinates has been noticed, particularly near the edges of images, and I am wondering if my neglect of coordinate system and projection is at fault. If I were to take it into account, what "projection" would my images be in? Could I simply convert to UTM Zone X for the computation, and convert the final result back to WGS84, or is UTM not an accurate representation of an image either?