Image manipulation

I need help with superimposing four graph images on top of each other to a single image. The challenge is get the graphs in correct relation to each other both in terms of size and in terms of placement in the graph coordinate system. This is a challenge because the four graphes have slightly different spacing on the x and y axis. (The machine outputting the graph images does this automatically, and it is not possible to get the coordinates of the different graphs from the machine.) My hope is therefore that someone with good photoshop skills, and images understanding, is able measure the difference in the scale of the two graphs, and find out how to re-size them so that they are on the same coordinate system, before superimposing them on top of each other, so that the final images shows the graphs in the correct relation to each other. More details; An example draft of how the final image should look can be found in the attached powerpoint file. The four graph images can be found in the attached word file. About the axis; The y axis LVP (mmHg) should contain only the number 132, and the X-axis strain should contain the numbers frrom -30 to 10 as demonstrated on the figures. The graphs, that all have the shape of a loop, will have to have different colours, so that they can be referenced in the text.