Digital cameras don't take photos of ANY given size.

Instead, they capture images with specific numbers of pixels, eg. 2048x3072 (my camera).

But if you know the print or display resolution of the intended application for these photos (eg. ID cards at 200dpi), then you can calculate the required number of pixels and then search for a camera which records images of that pixel dimension.

However.. nearly all digicams currently produce images with a 4:3 aspect ratio (Width == (1.3333 * Height)), or a 3:2 aspect ratio (most Digital SLRs), so I don't think you'll find one with a 1.5 : 1.25 ratio.

Cheers