You can combine two photos in one frame online using onlineconvertfree website.
Go to Onlineconvertfree and merge 2 photos online.
You can select the first and second image on the site. You can position the images horizontally or vertically.
If you want you can adjust the size of images by selecting border around the smaller image. You can also select the thickness of the border.
The website has a tutorial of 3 steps on how you can merge photos online.
If you need more such websites then try Merge two photos online for free.