how to combine pictures?

[yamaha83]

just starting to get my feet wet in photoshop and lightroom 2 and and my fiances sister really liked some pictures i did of her 2 kids in lightroom 2 and wanted me to combine a couple pics of the kids with another image kind of like a collage... the thing is that im not sure on the best way to do this? the picture she wanted me to use is a lot smaller of an image then the files i have of her kids so i tried to put them all in layers and make some maskes and do some free transforms to get the bigger pictures smaller and it just was not doing what i was thinking it would... that and im not real sure if i was doing it correctly... so any help would be awesome! im trying to get it done so she can make some prints for a Christmas present... thanks in advance!

[Cuervo79]

The first problem I see is the difference in resolution of the photos (since one is smaller than the others) first I would see what the final image size for printing is going to be and then make the canvas that size.

On the rest I would turn the photos to smart objects in order to size to my hearts content. Be informed that if the smaller photo is too small you'll get it pixelized no matter what you do when you upsize it. Also when free transforming remember to press the shift key before resizing so you maintain the original dimentions of the photo. Masking each layer is what I would do for a collage...

If you have a specific problem try to write about it since the only concrete problem you describe is the smaller photo, the rest of the process is a bit confusing, not sure what your real problem is there