reproject_image will produced incorrect results if the WCS in the file is defined as (DEC,RA) instead of (RA,DEC).
This is the case for some HST data.
This is the case for some HST data.
There is no handling of different celestial coord systems in reproject_image. If one file, for instance if B1950 and the other is J2000, the results will be obviously incorrect (e.g. negative axis ranges in the image).