Editing boarders in a photo

[wjh]

Hi,
This is a picture made with the Instacollage app.
I wanted to add two additional pictures.
How can I make the boarders of the 2 additional photos (the 2 which are down) fit perfectly or almost perfectly with the rest.View attachment Untitled-1.psd


Thanks a lot in advance,


WJH

 

[Steve]

Are you a Photoshop user?

 

[wjh]

Hi!
Thanks for your reply.
Yes I am, not an expert I would say..
I wanted to know what do you think is the best way to proceed in this case.

Best regards,

WJH

 

[wjh]

It's actually the first time I deal with this problem (borders a bit different..)