An image locking system for DNA micro-array synthesis provides a feedback system to stabilize or lock the image with respect to an image capture device, such as a camera and/or microscope. The image locking system includes the use of detection or reference marks. When a shift in image position is detected, a correction signal is sent to one of two mirrors, moving the image to correct for the shift in image position. The system comprises a first light beam directed towards a micromirror device that forms an alignment pattern on a reaction cell and a second light beam directed towards the micromirror device that forms a micro-array image on an active surface of the reaction cell. A camera captures the alignment pattern and an alignment mark. A computer calculates a correction signal to realign the alignment pattern with the alignment mark when movement is detected.