The scripts in my toolkit will resize your images to fill the image areas in your Collage template they are being populated into. The image composition in the collage will look like a centered aspect ratio crop that was resized to fill the image area in the collage. Image that are populated into collage template should have aspect ratios that are close the the Aspect Ratio of the area that they will be places into. Populating landscape images into portrait area or a portrait images into a landscape area will result in image composition that will be unacceptable for to much of you image content will be masked off. You can populate any size image they will be resized for the collage image area. However, for best results your Image should have the same Aspect ratio as the area they will be populated into. They are your images and they are your templates make then work well together..