It is possible to have several images open at the same time and you can use the Right Mouse Key Menu to Duplicate, Exchange with the Main Image or Send to the Main Image Windoow for a more detailed analysis:

It is possible to analyze differences of very similar images by subtracting an image from the Main Image. Before subtraction it can be an advantage to align the images by right clicking on Align To Main or ProcessingàOperate With MainàAlign All Images To Main (requires the Calibration or Movie Module), which will shift the current image in the x-y plane to give the best match defined by the cross correlation function.
When having more images of same size open it is possible to create profile at the exact same positions using the Synchronized Multi Profiling tool.
To open a group of files you can Drag Drop group of files or even entire folder branches from ImageMet Explorer or the MS Windows Explorer.
It is also possible to create a movie or a slide show of your images. First open the Movie Dialog and then add the images (frames) to the movie by right clicking on Add to Movie in the image window.
Mask Main
The two right-hand (color-clipping) markers determine upper and lower threshold. When clicking the Mask Main menu item then all pixels in the image with a value outside this interval will cause the corresponding position in the main image to be defined as void pixel.