  We present an algorithm to derive difference images for data taken with the
JWST with matched point-spread functions (PSFs). It is based on the saccadic
fast Fourier transform (SFFT) method but with revisions to accommodate the
rotations and spatial variations of the PSFs. It allows for spatially varying
kernels in B-spline form with separately controlled photometric scaling and
Tikhonov kernel regularization for harnessing the ultimate fitting flexibility.
We present this method using the JWST/NIRCam images of galaxy cluster Abell
2744 acquired in JWST Cycle 1 as the test data. The algorithm can be useful for
time-domain source detection and differential photometry with the JWST. It can
also coadd images of multiple exposures taken at different field orientations.
The coadded images preserve the sharpness of the central cores of the PSFs, and
the positions and shapes of the objects are matched precisely with B-splines
across the field.
