Same size and position of Screenshots

Hello all, 

i have a little problem that makes me crazy. ;-) 

I edit a course in which we describe our LMS. You see f.e. your user profil and you can click on different categories (data, courses,...), like in the LMS. Build with hotspots and states. My problem ist that my screenshots (made with snipping tool, mode snip window - so always same size) are not always on the same position. I always pull it on the same size, put it to the same position, but its always a little bit moved. 

Is a tickle work. Do you have any tipps how to make it easier? 

Kind regards,