The program Crop does not create the output image size as specified by the user if the size is an even number of pixels.

For example, with the following lines the user expects to have a final image of 6,6 pixels width, but the output is 7,7 pixels width.

astarithmetic 20 20 2 makenew 5 mknoise-sigma -o noise.fits

astcrop noise.fits --center=10,10 --width=6,6 --mode img -o crop.fits

astfits crop.fits

It is true that the situation is ambiguous because specifying a pixel center position and an image size with an even number of pixel is not well defined for the program Crop.

In this situation the program should crash and tell the user that there is a problem. It will be also useful to print the solution (use the option --section in this situation). Otherwise, if the user expects a X,Y image width but it provides a W,Z image width, it could cause a lot of confusion and problems later.