Verified answer

Forget Paint.

To put a person into a different photo/onto a different background:

You need a decent image editing program for a job like this (such as Photoshop, Elements, PaintShopPro or Gimp).

Open the person photo.

Promote the original background (layer) to a proper layer.

Select him/her via whichever selection tools works best for THAT image.

The more accurate you make this selection, the better the end result will look.

Delete the background, save the photo as a .psd or tiff or png file.

Open the new background photo. Grab the person's thumbnail from the layer window and drag/drop it onto the background image.

Transform to resize, move into position. Add a drop shadow to make it look more realistic.

Flatten and save.

Chances are there were a number of things you didn't understand, but you'll just have to work your way through it via reading help files and tutorials and/or getting out some books. Photoshop (or even Elements) requires quite some skill and YOU have to make the effort to get those skills. Alternatively, find someone who knows what they're doing and pay them for their skill and time.

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